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#ifdef RPC_DEBUG
 18# define RPCDBG_FACILITY	RPCDBG_AUTH
 19#endif
 20
 21#define RPC_MACHINE_CRED_USERID		((uid_t)0)
 22#define RPC_MACHINE_CRED_GROUPID	((gid_t)0)
 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
 41/*
 42 * Public call interface for looking up machine creds.
 43 */
 44struct rpc_cred *rpc_lookup_machine_cred(const char *service_name)
 45{
 46	struct auth_cred acred = {
 47		.uid = RPC_MACHINE_CRED_USERID,
 48		.gid = RPC_MACHINE_CRED_GROUPID,
 49		.principal = service_name,
 50		.machine_cred = 1,
 51	};
 52
 53	dprintk("RPC:       looking up machine cred for service %s\n",
 54			service_name);
 55	return generic_auth.au_ops->lookup_cred(&generic_auth, &acred, 0);
 56}
 57EXPORT_SYMBOL_GPL(rpc_lookup_machine_cred);
 58
 59static struct rpc_cred *generic_bind_cred(struct rpc_task *task,
 60		struct rpc_cred *cred, int lookupflags)
 61{
 62	struct rpc_auth *auth = task->tk_client->cl_auth;
 63	struct auth_cred *acred = &container_of(cred, struct generic_cred, gc_base)->acred;
 64
 65	return auth->au_ops->lookup_cred(auth, acred, lookupflags);
 66}
 67
 68/*
 69 * Lookup generic creds for current process
 70 */
 71static struct rpc_cred *
 72generic_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
 73{
 74	return rpcauth_lookup_credcache(&generic_auth, acred, flags);
 75}
 76
 77static struct rpc_cred *
 78generic_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
 79{
 80	struct generic_cred *gcred;
 81
 82	gcred = kmalloc(sizeof(*gcred), GFP_KERNEL);
 83	if (gcred == NULL)
 84		return ERR_PTR(-ENOMEM);
 85
 86	rpcauth_init_cred(&gcred->gc_base, acred, &generic_auth, &generic_credops);
 87	gcred->gc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
 88
 89	gcred->acred.uid = acred->uid;
 90	gcred->acred.gid = acred->gid;
 91	gcred->acred.group_info = acred->group_info;
 92	if (gcred->acred.group_info != NULL)
 93		get_group_info(gcred->acred.group_info);
 94	gcred->acred.machine_cred = acred->machine_cred;
 95	gcred->acred.principal = acred->principal;
 96
 97	dprintk("RPC:       allocated %s cred %p for uid %d gid %d\n",
 98			gcred->acred.machine_cred ? "machine" : "generic",
 99			gcred, acred->uid, acred->gid);
100	return &gcred->gc_base;
101}
102
103static void
104generic_free_cred(struct rpc_cred *cred)
105{
106	struct generic_cred *gcred = container_of(cred, struct generic_cred, gc_base);
107
108	dprintk("RPC:       generic_free_cred %p\n", gcred);
109	if (gcred->acred.group_info != NULL)
110		put_group_info(gcred->acred.group_info);
111	kfree(gcred);
112}
113
114static void
115generic_free_cred_callback(struct rcu_head *head)
116{
117	struct rpc_cred *cred = container_of(head, struct rpc_cred, cr_rcu);
118	generic_free_cred(cred);
119}
120
121static void
122generic_destroy_cred(struct rpc_cred *cred)
123{
124	call_rcu(&cred->cr_rcu, generic_free_cred_callback);
125}
126
127static int
128machine_cred_match(struct auth_cred *acred, struct generic_cred *gcred, int flags)
129{
130	if (!gcred->acred.machine_cred ||
131	    gcred->acred.principal != acred->principal ||
132	    gcred->acred.uid != acred->uid ||
133	    gcred->acred.gid != acred->gid)
134		return 0;
135	return 1;
136}
137
138/*
139 * Match credentials against current process creds.
140 */
141static int
142generic_match(struct auth_cred *acred, struct rpc_cred *cred, int flags)
143{
144	struct generic_cred *gcred = container_of(cred, struct generic_cred, gc_base);
145	int i;
146
147	if (acred->machine_cred)
148		return machine_cred_match(acred, gcred, flags);
149
150	if (gcred->acred.uid != acred->uid ||
151	    gcred->acred.gid != acred->gid ||
152	    gcred->acred.machine_cred != 0)
153		goto out_nomatch;
154
155	/* Optimisation in the case where pointers are identical... */
156	if (gcred->acred.group_info == acred->group_info)
157		goto out_match;
158
159	/* Slow path... */
160	if (gcred->acred.group_info->ngroups != acred->group_info->ngroups)
161		goto out_nomatch;
162	for (i = 0; i < gcred->acred.group_info->ngroups; i++) {
163		if (!gid_eq(GROUP_AT(gcred->acred.group_info, i),
164				GROUP_AT(acred->group_info, i)))
165			goto out_nomatch;
166	}
167out_match:
168	return 1;
169out_nomatch:
170	return 0;
171}
172
173int __init rpc_init_generic_auth(void)
174{
175	return rpcauth_init_credcache(&generic_auth);
176}
177
178void rpc_destroy_generic_auth(void)
179{
180	rpcauth_destroy_credcache(&generic_auth);
181}
182
183static const struct rpc_authops generic_auth_ops = {
184	.owner = THIS_MODULE,
185	.au_name = "Generic",
186	.lookup_cred = generic_lookup_cred,
187	.crcreate = generic_create_cred,
188};
189
190static struct rpc_auth generic_auth = {
191	.au_ops = &generic_auth_ops,
192	.au_count = ATOMIC_INIT(0),
193};
194
195static const struct rpc_credops generic_credops = {
196	.cr_name = "Generic cred",
197	.crdestroy = generic_destroy_cred,
198	.crbind = generic_bind_cred,
199	.crmatch = generic_match,
200};