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/net/sunrpc/auth_generic.c

http://github.com/mirrors/linux
C | 290 lines | 204 code | 43 blank | 43 comment | 24 complexity | 7df2d112b007de47b67d6b9d5ae5dd54 MD5 | raw file
  1/*
  2 * Generic RPC credential
  3 *
  4 * Copyright (C) 2008, Trond Myklebust <Trond.Myklebust@netapp.com>
  5 */
  6
  7#include <linux/err.h>
  8#include <linux/slab.h>
  9#include <linux/types.h>
 10#include <linux/module.h>
 11#include <linux/sched.h>
 12#include <linux/sunrpc/auth.h>
 13#include <linux/sunrpc/clnt.h>
 14#include <linux/sunrpc/debug.h>
 15#include <linux/sunrpc/sched.h>
 16
 17#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 18# define RPCDBG_FACILITY	RPCDBG_AUTH
 19#endif
 20
 21#define RPC_MACHINE_CRED_USERID		GLOBAL_ROOT_UID
 22#define RPC_MACHINE_CRED_GROUPID	GLOBAL_ROOT_GID
 23
 24struct generic_cred {
 25	struct rpc_cred gc_base;
 26	struct auth_cred acred;
 27};
 28
 29static struct rpc_auth generic_auth;
 30static const struct rpc_credops generic_credops;
 31
 32/*
 33 * Public call interface
 34 */
 35struct rpc_cred *rpc_lookup_cred(void)
 36{
 37	return rpcauth_lookupcred(&generic_auth, 0);
 38}
 39EXPORT_SYMBOL_GPL(rpc_lookup_cred);
 40
 41struct rpc_cred *
 42rpc_lookup_generic_cred(struct auth_cred *acred, int flags, gfp_t gfp)
 43{
 44	return rpcauth_lookup_credcache(&generic_auth, acred, flags, gfp);
 45}
 46EXPORT_SYMBOL_GPL(rpc_lookup_generic_cred);
 47
 48struct rpc_cred *rpc_lookup_cred_nonblock(void)
 49{
 50	return rpcauth_lookupcred(&generic_auth, RPCAUTH_LOOKUP_RCU);
 51}
 52EXPORT_SYMBOL_GPL(rpc_lookup_cred_nonblock);
 53
 54/*
 55 * Public call interface for looking up machine creds.
 56 */
 57struct rpc_cred *rpc_lookup_machine_cred(const char *service_name)
 58{
 59	struct auth_cred acred = {
 60		.uid = RPC_MACHINE_CRED_USERID,
 61		.gid = RPC_MACHINE_CRED_GROUPID,
 62		.principal = service_name,
 63		.machine_cred = 1,
 64	};
 65
 66	dprintk("RPC:       looking up machine cred for service %s\n",
 67			service_name);
 68	return generic_auth.au_ops->lookup_cred(&generic_auth, &acred, 0);
 69}
 70EXPORT_SYMBOL_GPL(rpc_lookup_machine_cred);
 71
 72static struct rpc_cred *generic_bind_cred(struct rpc_task *task,
 73		struct rpc_cred *cred, int lookupflags)
 74{
 75	struct rpc_auth *auth = task->tk_client->cl_auth;
 76	struct auth_cred *acred = &container_of(cred, struct generic_cred, gc_base)->acred;
 77
 78	return auth->au_ops->lookup_cred(auth, acred, lookupflags);
 79}
 80
 81/*
 82 * Lookup generic creds for current process
 83 */
 84static struct rpc_cred *
 85generic_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
 86{
 87	return rpcauth_lookup_credcache(&generic_auth, acred, flags, GFP_KERNEL);
 88}
 89
 90static struct rpc_cred *
 91generic_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags, gfp_t gfp)
 92{
 93	struct generic_cred *gcred;
 94
 95	gcred = kmalloc(sizeof(*gcred), gfp);
 96	if (gcred == NULL)
 97		return ERR_PTR(-ENOMEM);
 98
 99	rpcauth_init_cred(&gcred->gc_base, acred, &generic_auth, &generic_credops);
100	gcred->gc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
101
102	gcred->acred.uid = acred->uid;
103	gcred->acred.gid = acred->gid;
104	gcred->acred.group_info = acred->group_info;
105	gcred->acred.ac_flags = 0;
106	if (gcred->acred.group_info != NULL)
107		get_group_info(gcred->acred.group_info);
108	gcred->acred.machine_cred = acred->machine_cred;
109	gcred->acred.principal = acred->principal;
110
111	dprintk("RPC:       allocated %s cred %p for uid %d gid %d\n",
112			gcred->acred.machine_cred ? "machine" : "generic",
113			gcred,
114			from_kuid(&init_user_ns, acred->uid),
115			from_kgid(&init_user_ns, acred->gid));
116	return &gcred->gc_base;
117}
118
119static void
120generic_free_cred(struct rpc_cred *cred)
121{
122	struct generic_cred *gcred = container_of(cred, struct generic_cred, gc_base);
123
124	dprintk("RPC:       generic_free_cred %p\n", gcred);
125	if (gcred->acred.group_info != NULL)
126		put_group_info(gcred->acred.group_info);
127	kfree(gcred);
128}
129
130static void
131generic_free_cred_callback(struct rcu_head *head)
132{
133	struct rpc_cred *cred = container_of(head, struct rpc_cred, cr_rcu);
134	generic_free_cred(cred);
135}
136
137static void
138generic_destroy_cred(struct rpc_cred *cred)
139{
140	call_rcu(&cred->cr_rcu, generic_free_cred_callback);
141}
142
143static int
144machine_cred_match(struct auth_cred *acred, struct generic_cred *gcred, int flags)
145{
146	if (!gcred->acred.machine_cred ||
147	    gcred->acred.principal != acred->principal ||
148	    !uid_eq(gcred->acred.uid, acred->uid) ||
149	    !gid_eq(gcred->acred.gid, acred->gid))
150		return 0;
151	return 1;
152}
153
154/*
155 * Match credentials against current process creds.
156 */
157static int
158generic_match(struct auth_cred *acred, struct rpc_cred *cred, int flags)
159{
160	struct generic_cred *gcred = container_of(cred, struct generic_cred, gc_base);
161	int i;
162
163	if (acred->machine_cred)
164		return machine_cred_match(acred, gcred, flags);
165
166	if (!uid_eq(gcred->acred.uid, acred->uid) ||
167	    !gid_eq(gcred->acred.gid, acred->gid) ||
168	    gcred->acred.machine_cred != 0)
169		goto out_nomatch;
170
171	/* Optimisation in the case where pointers are identical... */
172	if (gcred->acred.group_info == acred->group_info)
173		goto out_match;
174
175	/* Slow path... */
176	if (gcred->acred.group_info->ngroups != acred->group_info->ngroups)
177		goto out_nomatch;
178	for (i = 0; i < gcred->acred.group_info->ngroups; i++) {
179		if (!gid_eq(GROUP_AT(gcred->acred.group_info, i),
180				GROUP_AT(acred->group_info, i)))
181			goto out_nomatch;
182	}
183out_match:
184	return 1;
185out_nomatch:
186	return 0;
187}
188
189int __init rpc_init_generic_auth(void)
190{
191	return rpcauth_init_credcache(&generic_auth);
192}
193
194void rpc_destroy_generic_auth(void)
195{
196	rpcauth_destroy_credcache(&generic_auth);
197}
198
199/*
200 * Test the the current time (now) against the underlying credential key expiry
201 * minus a timeout and setup notification.
202 *
203 * The normal case:
204 * If 'now' is before the key expiry minus RPC_KEY_EXPIRE_TIMEO, set
205 * the RPC_CRED_NOTIFY_TIMEOUT flag to setup the underlying credential
206 * rpc_credops crmatch routine to notify this generic cred when it's key
207 * expiration is within RPC_KEY_EXPIRE_TIMEO, and return 0.
208 *
209 * The error case:
210 * If the underlying cred lookup fails, return -EACCES.
211 *
212 * The 'almost' error case:
213 * If 'now' is within key expiry minus RPC_KEY_EXPIRE_TIMEO, but not within
214 * key expiry minus RPC_KEY_EXPIRE_FAIL, set the RPC_CRED_EXPIRE_SOON bit
215 * on the acred ac_flags and return 0.
216 */
217static int
218generic_key_timeout(struct rpc_auth *auth, struct rpc_cred *cred)
219{
220	struct auth_cred *acred = &container_of(cred, struct generic_cred,
221						gc_base)->acred;
222	struct rpc_cred *tcred;
223	int ret = 0;
224
225
226	/* Fast track for non crkey_timeout (no key) underlying credentials */
227	if (auth->au_flags & RPCAUTH_AUTH_NO_CRKEY_TIMEOUT)
228		return 0;
229
230	/* Fast track for the normal case */
231	if (test_bit(RPC_CRED_NOTIFY_TIMEOUT, &acred->ac_flags))
232		return 0;
233
234	/* lookup_cred either returns a valid referenced rpc_cred, or PTR_ERR */
235	tcred = auth->au_ops->lookup_cred(auth, acred, 0);
236	if (IS_ERR(tcred))
237		return -EACCES;
238
239	/* Test for the almost error case */
240	ret = tcred->cr_ops->crkey_timeout(tcred);
241	if (ret != 0) {
242		set_bit(RPC_CRED_KEY_EXPIRE_SOON, &acred->ac_flags);
243		ret = 0;
244	} else {
245		/* In case underlying cred key has been reset */
246		if (test_and_clear_bit(RPC_CRED_KEY_EXPIRE_SOON,
247					&acred->ac_flags))
248			dprintk("RPC:        UID %d Credential key reset\n",
249				from_kuid(&init_user_ns, tcred->cr_uid));
250		/* set up fasttrack for the normal case */
251		set_bit(RPC_CRED_NOTIFY_TIMEOUT, &acred->ac_flags);
252	}
253
254	put_rpccred(tcred);
255	return ret;
256}
257
258static const struct rpc_authops generic_auth_ops = {
259	.owner = THIS_MODULE,
260	.au_name = "Generic",
261	.lookup_cred = generic_lookup_cred,
262	.crcreate = generic_create_cred,
263	.key_timeout = generic_key_timeout,
264};
265
266static struct rpc_auth generic_auth = {
267	.au_ops = &generic_auth_ops,
268	.au_count = ATOMIC_INIT(0),
269};
270
271static bool generic_key_to_expire(struct rpc_cred *cred)
272{
273	struct auth_cred *acred = &container_of(cred, struct generic_cred,
274						gc_base)->acred;
275	bool ret;
276
277	get_rpccred(cred);
278	ret = test_bit(RPC_CRED_KEY_EXPIRE_SOON, &acred->ac_flags);
279	put_rpccred(cred);
280
281	return ret;
282}
283
284static const struct rpc_credops generic_credops = {
285	.cr_name = "Generic cred",
286	.crdestroy = generic_destroy_cred,
287	.crbind = generic_bind_cred,
288	.crmatch = generic_match,
289	.crkey_to_expire = generic_key_to_expire,
290};