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/sunrpc/msg_prot.h>
40 #include <linux/sunrpc/gss_asn1.h>
41 #include <linux/sunrpc/auth_gss.h>
42 #include <linux/sunrpc/svcauth_gss.h>
43 #include <linux/sunrpc/gss_err.h>
44 #include <linux/sunrpc/sched.h>
45 #include <linux/sunrpc/gss_api.h>
46 #include <linux/sunrpc/clnt.h>
47 
48 #ifdef RPC_DEBUG
49 # define RPCDBG_FACILITY        RPCDBG_AUTH
50 #endif
51 
52 static LIST_HEAD(registered_mechs);
53 static DEFINE_SPINLOCK(registered_mechs_lock);
54 
55 static void
56 gss_mech_free(struct gss_api_mech *gm)
57 {
58 	struct pf_desc *pf;
59 	int i;
60 
61 	for (i = 0; i < gm->gm_pf_num; i++) {
62 		pf = &gm->gm_pfs[i];
63 		kfree(pf->auth_domain_name);
64 		pf->auth_domain_name = NULL;
65 	}
66 }
67 
68 static inline char *
69 make_auth_domain_name(char *name)
70 {
71 	static char	*prefix = "gss/";
72 	char		*new;
73 
74 	new = kmalloc(strlen(name) + strlen(prefix) + 1, GFP_KERNEL);
75 	if (new) {
76 		strcpy(new, prefix);
77 		strcat(new, name);
78 	}
79 	return new;
80 }
81 
82 static int
83 gss_mech_svc_setup(struct gss_api_mech *gm)
84 {
85 	struct pf_desc *pf;
86 	int i, status;
87 
88 	for (i = 0; i < gm->gm_pf_num; i++) {
89 		pf = &gm->gm_pfs[i];
90 		pf->auth_domain_name = make_auth_domain_name(pf->name);
91 		status = -ENOMEM;
92 		if (pf->auth_domain_name == NULL)
93 			goto out;
94 		status = svcauth_gss_register_pseudoflavor(pf->pseudoflavor,
95 							pf->auth_domain_name);
96 		if (status)
97 			goto out;
98 	}
99 	return 0;
100 out:
101 	gss_mech_free(gm);
102 	return status;
103 }
104 
105 int
106 gss_mech_register(struct gss_api_mech *gm)
107 {
108 	int status;
109 
110 	status = gss_mech_svc_setup(gm);
111 	if (status)
112 		return status;
113 	spin_lock(&registered_mechs_lock);
114 	list_add(&gm->gm_list, &registered_mechs);
115 	spin_unlock(&registered_mechs_lock);
116 	dprintk("RPC:       registered gss mechanism %s\n", gm->gm_name);
117 	return 0;
118 }
119 
120 EXPORT_SYMBOL_GPL(gss_mech_register);
121 
122 void
123 gss_mech_unregister(struct gss_api_mech *gm)
124 {
125 	spin_lock(&registered_mechs_lock);
126 	list_del(&gm->gm_list);
127 	spin_unlock(&registered_mechs_lock);
128 	dprintk("RPC:       unregistered gss mechanism %s\n", gm->gm_name);
129 	gss_mech_free(gm);
130 }
131 
132 EXPORT_SYMBOL_GPL(gss_mech_unregister);
133 
134 struct gss_api_mech *
135 gss_mech_get(struct gss_api_mech *gm)
136 {
137 	__module_get(gm->gm_owner);
138 	return gm;
139 }
140 
141 EXPORT_SYMBOL_GPL(gss_mech_get);
142 
143 struct gss_api_mech *
144 _gss_mech_get_by_name(const char *name)
145 {
146 	struct gss_api_mech	*pos, *gm = NULL;
147 
148 	spin_lock(&registered_mechs_lock);
149 	list_for_each_entry(pos, &registered_mechs, gm_list) {
150 		if (0 == strcmp(name, pos->gm_name)) {
151 			if (try_module_get(pos->gm_owner))
152 				gm = pos;
153 			break;
154 		}
155 	}
156 	spin_unlock(&registered_mechs_lock);
157 	return gm;
158 
159 }
160 
161 struct gss_api_mech * gss_mech_get_by_name(const char *name)
162 {
163 	struct gss_api_mech *gm = NULL;
164 
165 	gm = _gss_mech_get_by_name(name);
166 	if (!gm) {
167 		request_module("rpc-auth-gss-%s", name);
168 		gm = _gss_mech_get_by_name(name);
169 	}
170 	return gm;
171 }
172 EXPORT_SYMBOL_GPL(gss_mech_get_by_name);
173 
174 struct gss_api_mech *
175 gss_mech_get_by_OID(struct xdr_netobj *obj)
176 {
177 	struct gss_api_mech	*pos, *gm = NULL;
178 
179 	spin_lock(&registered_mechs_lock);
180 	list_for_each_entry(pos, &registered_mechs, gm_list) {
181 		if (obj->len == pos->gm_oid.len) {
182 			if (0 == memcmp(obj->data, pos->gm_oid.data, obj->len)) {
183 				if (try_module_get(pos->gm_owner))
184 					gm = pos;
185 				break;
186 			}
187 		}
188 	}
189 	spin_unlock(&registered_mechs_lock);
190 	return gm;
191 
192 }
193 
194 EXPORT_SYMBOL_GPL(gss_mech_get_by_OID);
195 
196 static inline int
197 mech_supports_pseudoflavor(struct gss_api_mech *gm, u32 pseudoflavor)
198 {
199 	int i;
200 
201 	for (i = 0; i < gm->gm_pf_num; i++) {
202 		if (gm->gm_pfs[i].pseudoflavor == pseudoflavor)
203 			return 1;
204 	}
205 	return 0;
206 }
207 
208 struct gss_api_mech *_gss_mech_get_by_pseudoflavor(u32 pseudoflavor)
209 {
210 	struct gss_api_mech *gm = NULL, *pos;
211 
212 	spin_lock(&registered_mechs_lock);
213 	list_for_each_entry(pos, &registered_mechs, gm_list) {
214 		if (!mech_supports_pseudoflavor(pos, pseudoflavor)) {
215 			module_put(pos->gm_owner);
216 			continue;
217 		}
218 		if (try_module_get(pos->gm_owner))
219 			gm = pos;
220 		break;
221 	}
222 	spin_unlock(&registered_mechs_lock);
223 	return gm;
224 }
225 
226 struct gss_api_mech *
227 gss_mech_get_by_pseudoflavor(u32 pseudoflavor)
228 {
229 	struct gss_api_mech *gm;
230 
231 	gm = _gss_mech_get_by_pseudoflavor(pseudoflavor);
232 
233 	if (!gm) {
234 		request_module("rpc-auth-gss-%u", pseudoflavor);
235 		gm = _gss_mech_get_by_pseudoflavor(pseudoflavor);
236 	}
237 	return gm;
238 }
239 
240 EXPORT_SYMBOL_GPL(gss_mech_get_by_pseudoflavor);
241 
242 /**
243  * gss_mech_list_pseudoflavors - Discover registered GSS pseudoflavors
244  * @array: array to fill in
245  * @size: size of "array"
246  *
247  * Returns the number of array items filled in, or a negative errno.
248  *
249  * The returned array is not sorted by any policy.  Callers should not
250  * rely on the order of the items in the returned array.
251  */
252 int gss_mech_list_pseudoflavors(rpc_authflavor_t *array_ptr, int size)
253 {
254 	struct gss_api_mech *pos = NULL;
255 	int j, i = 0;
256 
257 	spin_lock(&registered_mechs_lock);
258 	list_for_each_entry(pos, &registered_mechs, gm_list) {
259 		for (j = 0; j < pos->gm_pf_num; j++) {
260 			if (i >= size)
261 				return -ENOMEM;
262 			array_ptr[i++] = pos->gm_pfs[j].pseudoflavor;
263 		}
264 	}
265 	spin_unlock(&registered_mechs_lock);
266 	return i;
267 }
268 
269 u32
270 gss_svc_to_pseudoflavor(struct gss_api_mech *gm, u32 service)
271 {
272 	int i;
273 
274 	for (i = 0; i < gm->gm_pf_num; i++) {
275 		if (gm->gm_pfs[i].service == service) {
276 			return gm->gm_pfs[i].pseudoflavor;
277 		}
278 	}
279 	return RPC_AUTH_MAXFLAVOR; /* illegal value */
280 }
281 EXPORT_SYMBOL_GPL(gss_svc_to_pseudoflavor);
282 
283 u32
284 gss_pseudoflavor_to_service(struct gss_api_mech *gm, u32 pseudoflavor)
285 {
286 	int i;
287 
288 	for (i = 0; i < gm->gm_pf_num; i++) {
289 		if (gm->gm_pfs[i].pseudoflavor == pseudoflavor)
290 			return gm->gm_pfs[i].service;
291 	}
292 	return 0;
293 }
294 
295 EXPORT_SYMBOL_GPL(gss_pseudoflavor_to_service);
296 
297 char *
298 gss_service_to_auth_domain_name(struct gss_api_mech *gm, u32 service)
299 {
300 	int i;
301 
302 	for (i = 0; i < gm->gm_pf_num; i++) {
303 		if (gm->gm_pfs[i].service == service)
304 			return gm->gm_pfs[i].auth_domain_name;
305 	}
306 	return NULL;
307 }
308 
309 EXPORT_SYMBOL_GPL(gss_service_to_auth_domain_name);
310 
311 void
312 gss_mech_put(struct gss_api_mech * gm)
313 {
314 	if (gm)
315 		module_put(gm->gm_owner);
316 }
317 
318 EXPORT_SYMBOL_GPL(gss_mech_put);
319 
320 /* The mech could probably be determined from the token instead, but it's just
321  * as easy for now to pass it in. */
322 int
323 gss_import_sec_context(const void *input_token, size_t bufsize,
324 		       struct gss_api_mech	*mech,
325 		       struct gss_ctx		**ctx_id,
326 		       gfp_t gfp_mask)
327 {
328 	if (!(*ctx_id = kzalloc(sizeof(**ctx_id), gfp_mask)))
329 		return -ENOMEM;
330 	(*ctx_id)->mech_type = gss_mech_get(mech);
331 
332 	return mech->gm_ops
333 		->gss_import_sec_context(input_token, bufsize, *ctx_id, gfp_mask);
334 }
335 
336 /* gss_get_mic: compute a mic over message and return mic_token. */
337 
338 u32
339 gss_get_mic(struct gss_ctx	*context_handle,
340 	    struct xdr_buf	*message,
341 	    struct xdr_netobj	*mic_token)
342 {
343 	 return context_handle->mech_type->gm_ops
344 		->gss_get_mic(context_handle,
345 			      message,
346 			      mic_token);
347 }
348 
349 /* gss_verify_mic: check whether the provided mic_token verifies message. */
350 
351 u32
352 gss_verify_mic(struct gss_ctx		*context_handle,
353 	       struct xdr_buf		*message,
354 	       struct xdr_netobj	*mic_token)
355 {
356 	return context_handle->mech_type->gm_ops
357 		->gss_verify_mic(context_handle,
358 				 message,
359 				 mic_token);
360 }
361 
362 /*
363  * This function is called from both the client and server code.
364  * Each makes guarantees about how much "slack" space is available
365  * for the underlying function in "buf"'s head and tail while
366  * performing the wrap.
367  *
368  * The client and server code allocate RPC_MAX_AUTH_SIZE extra
369  * space in both the head and tail which is available for use by
370  * the wrap function.
371  *
372  * Underlying functions should verify they do not use more than
373  * RPC_MAX_AUTH_SIZE of extra space in either the head or tail
374  * when performing the wrap.
375  */
376 u32
377 gss_wrap(struct gss_ctx	*ctx_id,
378 	 int		offset,
379 	 struct xdr_buf	*buf,
380 	 struct page	**inpages)
381 {
382 	return ctx_id->mech_type->gm_ops
383 		->gss_wrap(ctx_id, offset, buf, inpages);
384 }
385 
386 u32
387 gss_unwrap(struct gss_ctx	*ctx_id,
388 	   int			offset,
389 	   struct xdr_buf	*buf)
390 {
391 	return ctx_id->mech_type->gm_ops
392 		->gss_unwrap(ctx_id, offset, buf);
393 }
394 
395 
396 /* gss_delete_sec_context: free all resources associated with context_handle.
397  * Note this differs from the RFC 2744-specified prototype in that we don't
398  * bother returning an output token, since it would never be used anyway. */
399 
400 u32
401 gss_delete_sec_context(struct gss_ctx	**context_handle)
402 {
403 	dprintk("RPC:       gss_delete_sec_context deleting %p\n",
404 			*context_handle);
405 
406 	if (!*context_handle)
407 		return GSS_S_NO_CONTEXT;
408 	if ((*context_handle)->internal_ctx_id)
409 		(*context_handle)->mech_type->gm_ops
410 			->gss_delete_sec_context((*context_handle)
411 							->internal_ctx_id);
412 	gss_mech_put((*context_handle)->mech_type);
413 	kfree(*context_handle);
414 	*context_handle=NULL;
415 	return GSS_S_COMPLETE;
416 }
417