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