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 /**
107  * gss_mech_register - register a GSS mechanism
108  * @gm: GSS mechanism handle
109  *
110  * Returns zero if successful, or a negative errno.
111  */
112 int gss_mech_register(struct gss_api_mech *gm)
113 {
114 	int status;
115 
116 	status = gss_mech_svc_setup(gm);
117 	if (status)
118 		return status;
119 	spin_lock(&registered_mechs_lock);
120 	list_add(&gm->gm_list, &registered_mechs);
121 	spin_unlock(&registered_mechs_lock);
122 	dprintk("RPC:       registered gss mechanism %s\n", gm->gm_name);
123 	return 0;
124 }
125 EXPORT_SYMBOL_GPL(gss_mech_register);
126 
127 /**
128  * gss_mech_unregister - release a GSS mechanism
129  * @gm: GSS mechanism handle
130  *
131  */
132 void gss_mech_unregister(struct gss_api_mech *gm)
133 {
134 	spin_lock(&registered_mechs_lock);
135 	list_del(&gm->gm_list);
136 	spin_unlock(&registered_mechs_lock);
137 	dprintk("RPC:       unregistered gss mechanism %s\n", gm->gm_name);
138 	gss_mech_free(gm);
139 }
140 EXPORT_SYMBOL_GPL(gss_mech_unregister);
141 
142 static struct gss_api_mech *gss_mech_get(struct gss_api_mech *gm)
143 {
144 	__module_get(gm->gm_owner);
145 	return gm;
146 }
147 
148 static struct gss_api_mech *
149 _gss_mech_get_by_name(const char *name)
150 {
151 	struct gss_api_mech	*pos, *gm = NULL;
152 
153 	spin_lock(&registered_mechs_lock);
154 	list_for_each_entry(pos, &registered_mechs, gm_list) {
155 		if (0 == strcmp(name, pos->gm_name)) {
156 			if (try_module_get(pos->gm_owner))
157 				gm = pos;
158 			break;
159 		}
160 	}
161 	spin_unlock(&registered_mechs_lock);
162 	return gm;
163 
164 }
165 
166 struct gss_api_mech * gss_mech_get_by_name(const char *name)
167 {
168 	struct gss_api_mech *gm = NULL;
169 
170 	gm = _gss_mech_get_by_name(name);
171 	if (!gm) {
172 		request_module("rpc-auth-gss-%s", name);
173 		gm = _gss_mech_get_by_name(name);
174 	}
175 	return gm;
176 }
177 
178 struct gss_api_mech *gss_mech_get_by_OID(struct rpcsec_gss_oid *obj)
179 {
180 	struct gss_api_mech	*pos, *gm = NULL;
181 	char buf[32];
182 
183 	if (sprint_oid(obj->data, obj->len, buf, sizeof(buf)) < 0)
184 		return NULL;
185 	dprintk("RPC:       %s(%s)\n", __func__, buf);
186 	request_module("rpc-auth-gss-%s", buf);
187 
188 	spin_lock(&registered_mechs_lock);
189 	list_for_each_entry(pos, &registered_mechs, gm_list) {
190 		if (obj->len == pos->gm_oid.len) {
191 			if (0 == memcmp(obj->data, pos->gm_oid.data, obj->len)) {
192 				if (try_module_get(pos->gm_owner))
193 					gm = pos;
194 				break;
195 			}
196 		}
197 	}
198 	spin_unlock(&registered_mechs_lock);
199 	return gm;
200 }
201 
202 static inline int
203 mech_supports_pseudoflavor(struct gss_api_mech *gm, u32 pseudoflavor)
204 {
205 	int i;
206 
207 	for (i = 0; i < gm->gm_pf_num; i++) {
208 		if (gm->gm_pfs[i].pseudoflavor == pseudoflavor)
209 			return 1;
210 	}
211 	return 0;
212 }
213 
214 static struct gss_api_mech *_gss_mech_get_by_pseudoflavor(u32 pseudoflavor)
215 {
216 	struct gss_api_mech *gm = NULL, *pos;
217 
218 	spin_lock(&registered_mechs_lock);
219 	list_for_each_entry(pos, &registered_mechs, gm_list) {
220 		if (!mech_supports_pseudoflavor(pos, pseudoflavor)) {
221 			module_put(pos->gm_owner);
222 			continue;
223 		}
224 		if (try_module_get(pos->gm_owner))
225 			gm = pos;
226 		break;
227 	}
228 	spin_unlock(&registered_mechs_lock);
229 	return gm;
230 }
231 
232 struct gss_api_mech *
233 gss_mech_get_by_pseudoflavor(u32 pseudoflavor)
234 {
235 	struct gss_api_mech *gm;
236 
237 	gm = _gss_mech_get_by_pseudoflavor(pseudoflavor);
238 
239 	if (!gm) {
240 		request_module("rpc-auth-gss-%u", pseudoflavor);
241 		gm = _gss_mech_get_by_pseudoflavor(pseudoflavor);
242 	}
243 	return gm;
244 }
245 
246 /**
247  * gss_mech_list_pseudoflavors - Discover registered GSS pseudoflavors
248  * @array: array to fill in
249  * @size: size of "array"
250  *
251  * Returns the number of array items filled in, or a negative errno.
252  *
253  * The returned array is not sorted by any policy.  Callers should not
254  * rely on the order of the items in the returned array.
255  */
256 int gss_mech_list_pseudoflavors(rpc_authflavor_t *array_ptr, int size)
257 {
258 	struct gss_api_mech *pos = NULL;
259 	int j, i = 0;
260 
261 	spin_lock(&registered_mechs_lock);
262 	list_for_each_entry(pos, &registered_mechs, gm_list) {
263 		for (j = 0; j < pos->gm_pf_num; j++) {
264 			if (i >= size) {
265 				spin_unlock(&registered_mechs_lock);
266 				return -ENOMEM;
267 			}
268 			array_ptr[i++] = pos->gm_pfs[j].pseudoflavor;
269 		}
270 	}
271 	spin_unlock(&registered_mechs_lock);
272 	return i;
273 }
274 
275 /**
276  * gss_svc_to_pseudoflavor - map a GSS service number to a pseudoflavor
277  * @gm: GSS mechanism handle
278  * @qop: GSS quality-of-protection value
279  * @service: GSS service value
280  *
281  * Returns a matching security flavor, or RPC_AUTH_MAXFLAVOR if none is found.
282  */
283 rpc_authflavor_t gss_svc_to_pseudoflavor(struct gss_api_mech *gm, u32 qop,
284 					 u32 service)
285 {
286 	int i;
287 
288 	for (i = 0; i < gm->gm_pf_num; i++) {
289 		if (gm->gm_pfs[i].qop == qop &&
290 		    gm->gm_pfs[i].service == service) {
291 			return gm->gm_pfs[i].pseudoflavor;
292 		}
293 	}
294 	return RPC_AUTH_MAXFLAVOR;
295 }
296 
297 /**
298  * gss_mech_info2flavor - look up a pseudoflavor given a GSS tuple
299  * @info: a GSS mech OID, quality of protection, and service value
300  *
301  * Returns a matching pseudoflavor, or RPC_AUTH_MAXFLAVOR if the tuple is
302  * not supported.
303  */
304 rpc_authflavor_t gss_mech_info2flavor(struct rpcsec_gss_info *info)
305 {
306 	rpc_authflavor_t pseudoflavor;
307 	struct gss_api_mech *gm;
308 
309 	gm = gss_mech_get_by_OID(&info->oid);
310 	if (gm == NULL)
311 		return RPC_AUTH_MAXFLAVOR;
312 
313 	pseudoflavor = gss_svc_to_pseudoflavor(gm, info->qop, info->service);
314 
315 	gss_mech_put(gm);
316 	return pseudoflavor;
317 }
318 
319 /**
320  * gss_mech_flavor2info - look up a GSS tuple for a given pseudoflavor
321  * @pseudoflavor: GSS pseudoflavor to match
322  * @info: rpcsec_gss_info structure to fill in
323  *
324  * Returns zero and fills in "info" if pseudoflavor matches a
325  * supported mechanism.  Otherwise a negative errno is returned.
326  */
327 int gss_mech_flavor2info(rpc_authflavor_t pseudoflavor,
328 			 struct rpcsec_gss_info *info)
329 {
330 	struct gss_api_mech *gm;
331 	int i;
332 
333 	gm = gss_mech_get_by_pseudoflavor(pseudoflavor);
334 	if (gm == NULL)
335 		return -ENOENT;
336 
337 	for (i = 0; i < gm->gm_pf_num; i++) {
338 		if (gm->gm_pfs[i].pseudoflavor == pseudoflavor) {
339 			memcpy(info->oid.data, gm->gm_oid.data, gm->gm_oid.len);
340 			info->oid.len = gm->gm_oid.len;
341 			info->qop = gm->gm_pfs[i].qop;
342 			info->service = gm->gm_pfs[i].service;
343 			gss_mech_put(gm);
344 			return 0;
345 		}
346 	}
347 
348 	gss_mech_put(gm);
349 	return -ENOENT;
350 }
351 
352 u32
353 gss_pseudoflavor_to_service(struct gss_api_mech *gm, u32 pseudoflavor)
354 {
355 	int i;
356 
357 	for (i = 0; i < gm->gm_pf_num; i++) {
358 		if (gm->gm_pfs[i].pseudoflavor == pseudoflavor)
359 			return gm->gm_pfs[i].service;
360 	}
361 	return 0;
362 }
363 
364 char *
365 gss_service_to_auth_domain_name(struct gss_api_mech *gm, u32 service)
366 {
367 	int i;
368 
369 	for (i = 0; i < gm->gm_pf_num; i++) {
370 		if (gm->gm_pfs[i].service == service)
371 			return gm->gm_pfs[i].auth_domain_name;
372 	}
373 	return NULL;
374 }
375 
376 void
377 gss_mech_put(struct gss_api_mech * gm)
378 {
379 	if (gm)
380 		module_put(gm->gm_owner);
381 }
382 
383 /* The mech could probably be determined from the token instead, but it's just
384  * as easy for now to pass it in. */
385 int
386 gss_import_sec_context(const void *input_token, size_t bufsize,
387 		       struct gss_api_mech	*mech,
388 		       struct gss_ctx		**ctx_id,
389 		       time_t			*endtime,
390 		       gfp_t gfp_mask)
391 {
392 	if (!(*ctx_id = kzalloc(sizeof(**ctx_id), gfp_mask)))
393 		return -ENOMEM;
394 	(*ctx_id)->mech_type = gss_mech_get(mech);
395 
396 	return mech->gm_ops->gss_import_sec_context(input_token, bufsize,
397 						*ctx_id, endtime, gfp_mask);
398 }
399 
400 /* gss_get_mic: compute a mic over message and return mic_token. */
401 
402 u32
403 gss_get_mic(struct gss_ctx	*context_handle,
404 	    struct xdr_buf	*message,
405 	    struct xdr_netobj	*mic_token)
406 {
407 	 return context_handle->mech_type->gm_ops
408 		->gss_get_mic(context_handle,
409 			      message,
410 			      mic_token);
411 }
412 
413 /* gss_verify_mic: check whether the provided mic_token verifies message. */
414 
415 u32
416 gss_verify_mic(struct gss_ctx		*context_handle,
417 	       struct xdr_buf		*message,
418 	       struct xdr_netobj	*mic_token)
419 {
420 	return context_handle->mech_type->gm_ops
421 		->gss_verify_mic(context_handle,
422 				 message,
423 				 mic_token);
424 }
425 
426 /*
427  * This function is called from both the client and server code.
428  * Each makes guarantees about how much "slack" space is available
429  * for the underlying function in "buf"'s head and tail while
430  * performing the wrap.
431  *
432  * The client and server code allocate RPC_MAX_AUTH_SIZE extra
433  * space in both the head and tail which is available for use by
434  * the wrap function.
435  *
436  * Underlying functions should verify they do not use more than
437  * RPC_MAX_AUTH_SIZE of extra space in either the head or tail
438  * when performing the wrap.
439  */
440 u32
441 gss_wrap(struct gss_ctx	*ctx_id,
442 	 int		offset,
443 	 struct xdr_buf	*buf,
444 	 struct page	**inpages)
445 {
446 	return ctx_id->mech_type->gm_ops
447 		->gss_wrap(ctx_id, offset, buf, inpages);
448 }
449 
450 u32
451 gss_unwrap(struct gss_ctx	*ctx_id,
452 	   int			offset,
453 	   struct xdr_buf	*buf)
454 {
455 	return ctx_id->mech_type->gm_ops
456 		->gss_unwrap(ctx_id, offset, buf);
457 }
458 
459 
460 /* gss_delete_sec_context: free all resources associated with context_handle.
461  * Note this differs from the RFC 2744-specified prototype in that we don't
462  * bother returning an output token, since it would never be used anyway. */
463 
464 u32
465 gss_delete_sec_context(struct gss_ctx	**context_handle)
466 {
467 	dprintk("RPC:       gss_delete_sec_context deleting %p\n",
468 			*context_handle);
469 
470 	if (!*context_handle)
471 		return GSS_S_NO_CONTEXT;
472 	if ((*context_handle)->internal_ctx_id)
473 		(*context_handle)->mech_type->gm_ops
474 			->gss_delete_sec_context((*context_handle)
475 							->internal_ctx_id);
476 	gss_mech_put((*context_handle)->mech_type);
477 	kfree(*context_handle);
478 	*context_handle=NULL;
479 	return GSS_S_COMPLETE;
480 }
481