xref: /linux/net/sunrpc/auth.c (revision f3d9478b2ce468c3115b02ecae7e975990697f15) 
1 /*
2  * linux/net/sunrpc/auth.c
3  *
4  * Generic RPC client authentication API.
5  *
6  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
7  */
8 
9 #include <linux/types.h>
10 #include <linux/sched.h>
11 #include <linux/module.h>
12 #include <linux/slab.h>
13 #include <linux/errno.h>
14 #include <linux/sunrpc/clnt.h>
15 #include <linux/spinlock.h>
16 
17 #ifdef RPC_DEBUG
18 # define RPCDBG_FACILITY	RPCDBG_AUTH
19 #endif
20 
21 static struct rpc_authops *	auth_flavors[RPC_AUTH_MAXFLAVOR] = {
22 	&authnull_ops,		/* AUTH_NULL */
23 	&authunix_ops,		/* AUTH_UNIX */
24 	NULL,			/* others can be loadable modules */
25 };
26 
27 static u32
28 pseudoflavor_to_flavor(u32 flavor) {
29 	if (flavor >= RPC_AUTH_MAXFLAVOR)
30 		return RPC_AUTH_GSS;
31 	return flavor;
32 }
33 
34 int
35 rpcauth_register(struct rpc_authops *ops)
36 {
37 	rpc_authflavor_t flavor;
38 
39 	if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
40 		return -EINVAL;
41 	if (auth_flavors[flavor] != NULL)
42 		return -EPERM;		/* what else? */
43 	auth_flavors[flavor] = ops;
44 	return 0;
45 }
46 
47 int
48 rpcauth_unregister(struct rpc_authops *ops)
49 {
50 	rpc_authflavor_t flavor;
51 
52 	if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
53 		return -EINVAL;
54 	if (auth_flavors[flavor] != ops)
55 		return -EPERM;		/* what else? */
56 	auth_flavors[flavor] = NULL;
57 	return 0;
58 }
59 
60 struct rpc_auth *
61 rpcauth_create(rpc_authflavor_t pseudoflavor, struct rpc_clnt *clnt)
62 {
63 	struct rpc_auth		*auth;
64 	struct rpc_authops	*ops;
65 	u32			flavor = pseudoflavor_to_flavor(pseudoflavor);
66 
67 	auth = ERR_PTR(-EINVAL);
68 	if (flavor >= RPC_AUTH_MAXFLAVOR)
69 		goto out;
70 
71 	/* FIXME - auth_flavors[] really needs an rw lock,
72 	 * and module refcounting. */
73 #ifdef CONFIG_KMOD
74 	if ((ops = auth_flavors[flavor]) == NULL)
75 		request_module("rpc-auth-%u", flavor);
76 #endif
77 	if ((ops = auth_flavors[flavor]) == NULL)
78 		goto out;
79 	auth = ops->create(clnt, pseudoflavor);
80 	if (IS_ERR(auth))
81 		return auth;
82 	if (clnt->cl_auth)
83 		rpcauth_destroy(clnt->cl_auth);
84 	clnt->cl_auth = auth;
85 
86 out:
87 	return auth;
88 }
89 
90 void
91 rpcauth_destroy(struct rpc_auth *auth)
92 {
93 	if (!atomic_dec_and_test(&auth->au_count))
94 		return;
95 	auth->au_ops->destroy(auth);
96 }
97 
98 static DEFINE_SPINLOCK(rpc_credcache_lock);
99 
100 /*
101  * Initialize RPC credential cache
102  */
103 int
104 rpcauth_init_credcache(struct rpc_auth *auth, unsigned long expire)
105 {
106 	struct rpc_cred_cache *new;
107 	int i;
108 
109 	new = kmalloc(sizeof(*new), GFP_KERNEL);
110 	if (!new)
111 		return -ENOMEM;
112 	for (i = 0; i < RPC_CREDCACHE_NR; i++)
113 		INIT_HLIST_HEAD(&new->hashtable[i]);
114 	new->expire = expire;
115 	new->nextgc = jiffies + (expire >> 1);
116 	auth->au_credcache = new;
117 	return 0;
118 }
119 
120 /*
121  * Destroy a list of credentials
122  */
123 static inline
124 void rpcauth_destroy_credlist(struct hlist_head *head)
125 {
126 	struct rpc_cred *cred;
127 
128 	while (!hlist_empty(head)) {
129 		cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
130 		hlist_del_init(&cred->cr_hash);
131 		put_rpccred(cred);
132 	}
133 }
134 
135 /*
136  * Clear the RPC credential cache, and delete those credentials
137  * that are not referenced.
138  */
139 void
140 rpcauth_free_credcache(struct rpc_auth *auth)
141 {
142 	struct rpc_cred_cache *cache = auth->au_credcache;
143 	HLIST_HEAD(free);
144 	struct hlist_node *pos, *next;
145 	struct rpc_cred	*cred;
146 	int		i;
147 
148 	spin_lock(&rpc_credcache_lock);
149 	for (i = 0; i < RPC_CREDCACHE_NR; i++) {
150 		hlist_for_each_safe(pos, next, &cache->hashtable[i]) {
151 			cred = hlist_entry(pos, struct rpc_cred, cr_hash);
152 			__hlist_del(&cred->cr_hash);
153 			hlist_add_head(&cred->cr_hash, &free);
154 		}
155 	}
156 	spin_unlock(&rpc_credcache_lock);
157 	rpcauth_destroy_credlist(&free);
158 }
159 
160 static void
161 rpcauth_prune_expired(struct rpc_auth *auth, struct rpc_cred *cred, struct hlist_head *free)
162 {
163 	if (atomic_read(&cred->cr_count) != 1)
164 	       return;
165 	if (time_after(jiffies, cred->cr_expire + auth->au_credcache->expire))
166 		cred->cr_flags &= ~RPCAUTH_CRED_UPTODATE;
167 	if (!(cred->cr_flags & RPCAUTH_CRED_UPTODATE)) {
168 		__hlist_del(&cred->cr_hash);
169 		hlist_add_head(&cred->cr_hash, free);
170 	}
171 }
172 
173 /*
174  * Remove stale credentials. Avoid sleeping inside the loop.
175  */
176 static void
177 rpcauth_gc_credcache(struct rpc_auth *auth, struct hlist_head *free)
178 {
179 	struct rpc_cred_cache *cache = auth->au_credcache;
180 	struct hlist_node *pos, *next;
181 	struct rpc_cred	*cred;
182 	int		i;
183 
184 	dprintk("RPC: gc'ing RPC credentials for auth %p\n", auth);
185 	for (i = 0; i < RPC_CREDCACHE_NR; i++) {
186 		hlist_for_each_safe(pos, next, &cache->hashtable[i]) {
187 			cred = hlist_entry(pos, struct rpc_cred, cr_hash);
188 			rpcauth_prune_expired(auth, cred, free);
189 		}
190 	}
191 	cache->nextgc = jiffies + cache->expire;
192 }
193 
194 /*
195  * Look up a process' credentials in the authentication cache
196  */
197 struct rpc_cred *
198 rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
199 		int flags)
200 {
201 	struct rpc_cred_cache *cache = auth->au_credcache;
202 	HLIST_HEAD(free);
203 	struct hlist_node *pos, *next;
204 	struct rpc_cred	*new = NULL,
205 			*cred = NULL;
206 	int		nr = 0;
207 
208 	if (!(flags & RPCAUTH_LOOKUP_ROOTCREDS))
209 		nr = acred->uid & RPC_CREDCACHE_MASK;
210 retry:
211 	spin_lock(&rpc_credcache_lock);
212 	if (time_before(cache->nextgc, jiffies))
213 		rpcauth_gc_credcache(auth, &free);
214 	hlist_for_each_safe(pos, next, &cache->hashtable[nr]) {
215 		struct rpc_cred *entry;
216 	       	entry = hlist_entry(pos, struct rpc_cred, cr_hash);
217 		if (entry->cr_ops->crmatch(acred, entry, flags)) {
218 			hlist_del(&entry->cr_hash);
219 			cred = entry;
220 			break;
221 		}
222 		rpcauth_prune_expired(auth, entry, &free);
223 	}
224 	if (new) {
225 		if (cred)
226 			hlist_add_head(&new->cr_hash, &free);
227 		else
228 			cred = new;
229 	}
230 	if (cred) {
231 		hlist_add_head(&cred->cr_hash, &cache->hashtable[nr]);
232 		get_rpccred(cred);
233 	}
234 	spin_unlock(&rpc_credcache_lock);
235 
236 	rpcauth_destroy_credlist(&free);
237 
238 	if (!cred) {
239 		new = auth->au_ops->crcreate(auth, acred, flags);
240 		if (!IS_ERR(new)) {
241 #ifdef RPC_DEBUG
242 			new->cr_magic = RPCAUTH_CRED_MAGIC;
243 #endif
244 			goto retry;
245 		} else
246 			cred = new;
247 	} else if ((cred->cr_flags & RPCAUTH_CRED_NEW)
248 			&& cred->cr_ops->cr_init != NULL
249 			&& !(flags & RPCAUTH_LOOKUP_NEW)) {
250 		int res = cred->cr_ops->cr_init(auth, cred);
251 		if (res < 0) {
252 			put_rpccred(cred);
253 			cred = ERR_PTR(res);
254 		}
255 	}
256 
257 	return (struct rpc_cred *) cred;
258 }
259 
260 struct rpc_cred *
261 rpcauth_lookupcred(struct rpc_auth *auth, int flags)
262 {
263 	struct auth_cred acred = {
264 		.uid = current->fsuid,
265 		.gid = current->fsgid,
266 		.group_info = current->group_info,
267 	};
268 	struct rpc_cred *ret;
269 
270 	dprintk("RPC:     looking up %s cred\n",
271 		auth->au_ops->au_name);
272 	get_group_info(acred.group_info);
273 	ret = auth->au_ops->lookup_cred(auth, &acred, flags);
274 	put_group_info(acred.group_info);
275 	return ret;
276 }
277 
278 struct rpc_cred *
279 rpcauth_bindcred(struct rpc_task *task)
280 {
281 	struct rpc_auth *auth = task->tk_auth;
282 	struct auth_cred acred = {
283 		.uid = current->fsuid,
284 		.gid = current->fsgid,
285 		.group_info = current->group_info,
286 	};
287 	struct rpc_cred *ret;
288 	int flags = 0;
289 
290 	dprintk("RPC: %4d looking up %s cred\n",
291 		task->tk_pid, task->tk_auth->au_ops->au_name);
292 	get_group_info(acred.group_info);
293 	if (task->tk_flags & RPC_TASK_ROOTCREDS)
294 		flags |= RPCAUTH_LOOKUP_ROOTCREDS;
295 	ret = auth->au_ops->lookup_cred(auth, &acred, flags);
296 	if (!IS_ERR(ret))
297 		task->tk_msg.rpc_cred = ret;
298 	else
299 		task->tk_status = PTR_ERR(ret);
300 	put_group_info(acred.group_info);
301 	return ret;
302 }
303 
304 void
305 rpcauth_holdcred(struct rpc_task *task)
306 {
307 	dprintk("RPC: %4d holding %s cred %p\n",
308 		task->tk_pid, task->tk_auth->au_ops->au_name, task->tk_msg.rpc_cred);
309 	if (task->tk_msg.rpc_cred)
310 		get_rpccred(task->tk_msg.rpc_cred);
311 }
312 
313 void
314 put_rpccred(struct rpc_cred *cred)
315 {
316 	cred->cr_expire = jiffies;
317 	if (!atomic_dec_and_test(&cred->cr_count))
318 		return;
319 	cred->cr_ops->crdestroy(cred);
320 }
321 
322 void
323 rpcauth_unbindcred(struct rpc_task *task)
324 {
325 	struct rpc_cred	*cred = task->tk_msg.rpc_cred;
326 
327 	dprintk("RPC: %4d releasing %s cred %p\n",
328 		task->tk_pid, task->tk_auth->au_ops->au_name, cred);
329 
330 	put_rpccred(cred);
331 	task->tk_msg.rpc_cred = NULL;
332 }
333 
334 u32 *
335 rpcauth_marshcred(struct rpc_task *task, u32 *p)
336 {
337 	struct rpc_cred	*cred = task->tk_msg.rpc_cred;
338 
339 	dprintk("RPC: %4d marshaling %s cred %p\n",
340 		task->tk_pid, task->tk_auth->au_ops->au_name, cred);
341 
342 	return cred->cr_ops->crmarshal(task, p);
343 }
344 
345 u32 *
346 rpcauth_checkverf(struct rpc_task *task, u32 *p)
347 {
348 	struct rpc_cred	*cred = task->tk_msg.rpc_cred;
349 
350 	dprintk("RPC: %4d validating %s cred %p\n",
351 		task->tk_pid, task->tk_auth->au_ops->au_name, cred);
352 
353 	return cred->cr_ops->crvalidate(task, p);
354 }
355 
356 int
357 rpcauth_wrap_req(struct rpc_task *task, kxdrproc_t encode, void *rqstp,
358 		u32 *data, void *obj)
359 {
360 	struct rpc_cred *cred = task->tk_msg.rpc_cred;
361 
362 	dprintk("RPC: %4d using %s cred %p to wrap rpc data\n",
363 			task->tk_pid, cred->cr_ops->cr_name, cred);
364 	if (cred->cr_ops->crwrap_req)
365 		return cred->cr_ops->crwrap_req(task, encode, rqstp, data, obj);
366 	/* By default, we encode the arguments normally. */
367 	return encode(rqstp, data, obj);
368 }
369 
370 int
371 rpcauth_unwrap_resp(struct rpc_task *task, kxdrproc_t decode, void *rqstp,
372 		u32 *data, void *obj)
373 {
374 	struct rpc_cred *cred = task->tk_msg.rpc_cred;
375 
376 	dprintk("RPC: %4d using %s cred %p to unwrap rpc data\n",
377 			task->tk_pid, cred->cr_ops->cr_name, cred);
378 	if (cred->cr_ops->crunwrap_resp)
379 		return cred->cr_ops->crunwrap_resp(task, decode, rqstp,
380 						   data, obj);
381 	/* By default, we decode the arguments normally. */
382 	return decode(rqstp, data, obj);
383 }
384 
385 int
386 rpcauth_refreshcred(struct rpc_task *task)
387 {
388 	struct rpc_cred	*cred = task->tk_msg.rpc_cred;
389 	int err;
390 
391 	dprintk("RPC: %4d refreshing %s cred %p\n",
392 		task->tk_pid, task->tk_auth->au_ops->au_name, cred);
393 
394 	err = cred->cr_ops->crrefresh(task);
395 	if (err < 0)
396 		task->tk_status = err;
397 	return err;
398 }
399 
400 void
401 rpcauth_invalcred(struct rpc_task *task)
402 {
403 	dprintk("RPC: %4d invalidating %s cred %p\n",
404 		task->tk_pid, task->tk_auth->au_ops->au_name, task->tk_msg.rpc_cred);
405 	spin_lock(&rpc_credcache_lock);
406 	if (task->tk_msg.rpc_cred)
407 		task->tk_msg.rpc_cred->cr_flags &= ~RPCAUTH_CRED_UPTODATE;
408 	spin_unlock(&rpc_credcache_lock);
409 }
410 
411 int
412 rpcauth_uptodatecred(struct rpc_task *task)
413 {
414 	return !(task->tk_msg.rpc_cred) ||
415 		(task->tk_msg.rpc_cred->cr_flags & RPCAUTH_CRED_UPTODATE);
416 }
417