xref: /linux/net/sunrpc/auth.c (revision d8327c784b51b57dac2c26cfad87dce0d68dfd98) 
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 	if (flavor >= RPC_AUTH_MAXFLAVOR || !(ops = auth_flavors[flavor]))
68 		return ERR_PTR(-EINVAL);
69 	auth = ops->create(clnt, pseudoflavor);
70 	if (IS_ERR(auth))
71 		return auth;
72 	if (clnt->cl_auth)
73 		rpcauth_destroy(clnt->cl_auth);
74 	clnt->cl_auth = auth;
75 	return auth;
76 }
77 
78 void
79 rpcauth_destroy(struct rpc_auth *auth)
80 {
81 	if (!atomic_dec_and_test(&auth->au_count))
82 		return;
83 	auth->au_ops->destroy(auth);
84 }
85 
86 static DEFINE_SPINLOCK(rpc_credcache_lock);
87 
88 /*
89  * Initialize RPC credential cache
90  */
91 int
92 rpcauth_init_credcache(struct rpc_auth *auth, unsigned long expire)
93 {
94 	struct rpc_cred_cache *new;
95 	int i;
96 
97 	new = kmalloc(sizeof(*new), GFP_KERNEL);
98 	if (!new)
99 		return -ENOMEM;
100 	for (i = 0; i < RPC_CREDCACHE_NR; i++)
101 		INIT_HLIST_HEAD(&new->hashtable[i]);
102 	new->expire = expire;
103 	new->nextgc = jiffies + (expire >> 1);
104 	auth->au_credcache = new;
105 	return 0;
106 }
107 
108 /*
109  * Destroy a list of credentials
110  */
111 static inline
112 void rpcauth_destroy_credlist(struct hlist_head *head)
113 {
114 	struct rpc_cred *cred;
115 
116 	while (!hlist_empty(head)) {
117 		cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
118 		hlist_del_init(&cred->cr_hash);
119 		put_rpccred(cred);
120 	}
121 }
122 
123 /*
124  * Clear the RPC credential cache, and delete those credentials
125  * that are not referenced.
126  */
127 void
128 rpcauth_free_credcache(struct rpc_auth *auth)
129 {
130 	struct rpc_cred_cache *cache = auth->au_credcache;
131 	HLIST_HEAD(free);
132 	struct hlist_node *pos, *next;
133 	struct rpc_cred	*cred;
134 	int		i;
135 
136 	spin_lock(&rpc_credcache_lock);
137 	for (i = 0; i < RPC_CREDCACHE_NR; i++) {
138 		hlist_for_each_safe(pos, next, &cache->hashtable[i]) {
139 			cred = hlist_entry(pos, struct rpc_cred, cr_hash);
140 			__hlist_del(&cred->cr_hash);
141 			hlist_add_head(&cred->cr_hash, &free);
142 		}
143 	}
144 	spin_unlock(&rpc_credcache_lock);
145 	rpcauth_destroy_credlist(&free);
146 }
147 
148 static void
149 rpcauth_prune_expired(struct rpc_auth *auth, struct rpc_cred *cred, struct hlist_head *free)
150 {
151 	if (atomic_read(&cred->cr_count) != 1)
152 	       return;
153 	if (time_after(jiffies, cred->cr_expire + auth->au_credcache->expire))
154 		cred->cr_flags &= ~RPCAUTH_CRED_UPTODATE;
155 	if (!(cred->cr_flags & RPCAUTH_CRED_UPTODATE)) {
156 		__hlist_del(&cred->cr_hash);
157 		hlist_add_head(&cred->cr_hash, free);
158 	}
159 }
160 
161 /*
162  * Remove stale credentials. Avoid sleeping inside the loop.
163  */
164 static void
165 rpcauth_gc_credcache(struct rpc_auth *auth, struct hlist_head *free)
166 {
167 	struct rpc_cred_cache *cache = auth->au_credcache;
168 	struct hlist_node *pos, *next;
169 	struct rpc_cred	*cred;
170 	int		i;
171 
172 	dprintk("RPC: gc'ing RPC credentials for auth %p\n", auth);
173 	for (i = 0; i < RPC_CREDCACHE_NR; i++) {
174 		hlist_for_each_safe(pos, next, &cache->hashtable[i]) {
175 			cred = hlist_entry(pos, struct rpc_cred, cr_hash);
176 			rpcauth_prune_expired(auth, cred, free);
177 		}
178 	}
179 	cache->nextgc = jiffies + cache->expire;
180 }
181 
182 /*
183  * Look up a process' credentials in the authentication cache
184  */
185 struct rpc_cred *
186 rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
187 		int flags)
188 {
189 	struct rpc_cred_cache *cache = auth->au_credcache;
190 	HLIST_HEAD(free);
191 	struct hlist_node *pos, *next;
192 	struct rpc_cred	*new = NULL,
193 			*cred = NULL;
194 	int		nr = 0;
195 
196 	if (!(flags & RPCAUTH_LOOKUP_ROOTCREDS))
197 		nr = acred->uid & RPC_CREDCACHE_MASK;
198 retry:
199 	spin_lock(&rpc_credcache_lock);
200 	if (time_before(cache->nextgc, jiffies))
201 		rpcauth_gc_credcache(auth, &free);
202 	hlist_for_each_safe(pos, next, &cache->hashtable[nr]) {
203 		struct rpc_cred *entry;
204 	       	entry = hlist_entry(pos, struct rpc_cred, cr_hash);
205 		if (entry->cr_ops->crmatch(acred, entry, flags)) {
206 			hlist_del(&entry->cr_hash);
207 			cred = entry;
208 			break;
209 		}
210 		rpcauth_prune_expired(auth, entry, &free);
211 	}
212 	if (new) {
213 		if (cred)
214 			hlist_add_head(&new->cr_hash, &free);
215 		else
216 			cred = new;
217 	}
218 	if (cred) {
219 		hlist_add_head(&cred->cr_hash, &cache->hashtable[nr]);
220 		get_rpccred(cred);
221 	}
222 	spin_unlock(&rpc_credcache_lock);
223 
224 	rpcauth_destroy_credlist(&free);
225 
226 	if (!cred) {
227 		new = auth->au_ops->crcreate(auth, acred, flags);
228 		if (!IS_ERR(new)) {
229 #ifdef RPC_DEBUG
230 			new->cr_magic = RPCAUTH_CRED_MAGIC;
231 #endif
232 			goto retry;
233 		} else
234 			cred = new;
235 	} else if ((cred->cr_flags & RPCAUTH_CRED_NEW)
236 			&& cred->cr_ops->cr_init != NULL
237 			&& !(flags & RPCAUTH_LOOKUP_NEW)) {
238 		int res = cred->cr_ops->cr_init(auth, cred);
239 		if (res < 0) {
240 			put_rpccred(cred);
241 			cred = ERR_PTR(res);
242 		}
243 	}
244 
245 	return (struct rpc_cred *) cred;
246 }
247 
248 struct rpc_cred *
249 rpcauth_lookupcred(struct rpc_auth *auth, int flags)
250 {
251 	struct auth_cred acred = {
252 		.uid = current->fsuid,
253 		.gid = current->fsgid,
254 		.group_info = current->group_info,
255 	};
256 	struct rpc_cred *ret;
257 
258 	dprintk("RPC:     looking up %s cred\n",
259 		auth->au_ops->au_name);
260 	get_group_info(acred.group_info);
261 	ret = auth->au_ops->lookup_cred(auth, &acred, flags);
262 	put_group_info(acred.group_info);
263 	return ret;
264 }
265 
266 struct rpc_cred *
267 rpcauth_bindcred(struct rpc_task *task)
268 {
269 	struct rpc_auth *auth = task->tk_auth;
270 	struct auth_cred acred = {
271 		.uid = current->fsuid,
272 		.gid = current->fsgid,
273 		.group_info = current->group_info,
274 	};
275 	struct rpc_cred *ret;
276 	int flags = 0;
277 
278 	dprintk("RPC: %4d looking up %s cred\n",
279 		task->tk_pid, task->tk_auth->au_ops->au_name);
280 	get_group_info(acred.group_info);
281 	if (task->tk_flags & RPC_TASK_ROOTCREDS)
282 		flags |= RPCAUTH_LOOKUP_ROOTCREDS;
283 	ret = auth->au_ops->lookup_cred(auth, &acred, flags);
284 	if (!IS_ERR(ret))
285 		task->tk_msg.rpc_cred = ret;
286 	else
287 		task->tk_status = PTR_ERR(ret);
288 	put_group_info(acred.group_info);
289 	return ret;
290 }
291 
292 void
293 rpcauth_holdcred(struct rpc_task *task)
294 {
295 	dprintk("RPC: %4d holding %s cred %p\n",
296 		task->tk_pid, task->tk_auth->au_ops->au_name, task->tk_msg.rpc_cred);
297 	if (task->tk_msg.rpc_cred)
298 		get_rpccred(task->tk_msg.rpc_cred);
299 }
300 
301 void
302 put_rpccred(struct rpc_cred *cred)
303 {
304 	cred->cr_expire = jiffies;
305 	if (!atomic_dec_and_test(&cred->cr_count))
306 		return;
307 	cred->cr_ops->crdestroy(cred);
308 }
309 
310 void
311 rpcauth_unbindcred(struct rpc_task *task)
312 {
313 	struct rpc_cred	*cred = task->tk_msg.rpc_cred;
314 
315 	dprintk("RPC: %4d releasing %s cred %p\n",
316 		task->tk_pid, task->tk_auth->au_ops->au_name, cred);
317 
318 	put_rpccred(cred);
319 	task->tk_msg.rpc_cred = NULL;
320 }
321 
322 u32 *
323 rpcauth_marshcred(struct rpc_task *task, u32 *p)
324 {
325 	struct rpc_cred	*cred = task->tk_msg.rpc_cred;
326 
327 	dprintk("RPC: %4d marshaling %s cred %p\n",
328 		task->tk_pid, task->tk_auth->au_ops->au_name, cred);
329 
330 	return cred->cr_ops->crmarshal(task, p);
331 }
332 
333 u32 *
334 rpcauth_checkverf(struct rpc_task *task, u32 *p)
335 {
336 	struct rpc_cred	*cred = task->tk_msg.rpc_cred;
337 
338 	dprintk("RPC: %4d validating %s cred %p\n",
339 		task->tk_pid, task->tk_auth->au_ops->au_name, cred);
340 
341 	return cred->cr_ops->crvalidate(task, p);
342 }
343 
344 int
345 rpcauth_wrap_req(struct rpc_task *task, kxdrproc_t encode, void *rqstp,
346 		u32 *data, void *obj)
347 {
348 	struct rpc_cred *cred = task->tk_msg.rpc_cred;
349 
350 	dprintk("RPC: %4d using %s cred %p to wrap rpc data\n",
351 			task->tk_pid, cred->cr_ops->cr_name, cred);
352 	if (cred->cr_ops->crwrap_req)
353 		return cred->cr_ops->crwrap_req(task, encode, rqstp, data, obj);
354 	/* By default, we encode the arguments normally. */
355 	return encode(rqstp, data, obj);
356 }
357 
358 int
359 rpcauth_unwrap_resp(struct rpc_task *task, kxdrproc_t decode, void *rqstp,
360 		u32 *data, void *obj)
361 {
362 	struct rpc_cred *cred = task->tk_msg.rpc_cred;
363 
364 	dprintk("RPC: %4d using %s cred %p to unwrap rpc data\n",
365 			task->tk_pid, cred->cr_ops->cr_name, cred);
366 	if (cred->cr_ops->crunwrap_resp)
367 		return cred->cr_ops->crunwrap_resp(task, decode, rqstp,
368 						   data, obj);
369 	/* By default, we decode the arguments normally. */
370 	return decode(rqstp, data, obj);
371 }
372 
373 int
374 rpcauth_refreshcred(struct rpc_task *task)
375 {
376 	struct rpc_cred	*cred = task->tk_msg.rpc_cred;
377 	int err;
378 
379 	dprintk("RPC: %4d refreshing %s cred %p\n",
380 		task->tk_pid, task->tk_auth->au_ops->au_name, cred);
381 
382 	err = cred->cr_ops->crrefresh(task);
383 	if (err < 0)
384 		task->tk_status = err;
385 	return err;
386 }
387 
388 void
389 rpcauth_invalcred(struct rpc_task *task)
390 {
391 	dprintk("RPC: %4d invalidating %s cred %p\n",
392 		task->tk_pid, task->tk_auth->au_ops->au_name, task->tk_msg.rpc_cred);
393 	spin_lock(&rpc_credcache_lock);
394 	if (task->tk_msg.rpc_cred)
395 		task->tk_msg.rpc_cred->cr_flags &= ~RPCAUTH_CRED_UPTODATE;
396 	spin_unlock(&rpc_credcache_lock);
397 }
398 
399 int
400 rpcauth_uptodatecred(struct rpc_task *task)
401 {
402 	return !(task->tk_msg.rpc_cred) ||
403 		(task->tk_msg.rpc_cred->cr_flags & RPCAUTH_CRED_UPTODATE);
404 }
405