1/*
2 * linux/net/sunrpc/auth_unix.c
3 *
4 * UNIX-style authentication; no AUTH_SHORT support
5 *
6 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
7 */
8
9#include <linux/slab.h>
10#include <linux/types.h>
11#include <linux/sched.h>
12#include <linux/module.h>
13#include <linux/sunrpc/clnt.h>
14#include <linux/sunrpc/auth.h>
15
16#define NFS_NGROUPS	16
17
18struct unx_cred {
19	struct rpc_cred		uc_base;
20	gid_t			uc_gid;
21	gid_t			uc_gids[NFS_NGROUPS];
22};
23#define uc_uid			uc_base.cr_uid
24
25#define UNX_WRITESLACK		(21 + (UNX_MAXNODENAME >> 2))
26
27#ifdef RPC_DEBUG
28# define RPCDBG_FACILITY	RPCDBG_AUTH
29#endif
30
31static struct rpc_auth		unix_auth;
32static const struct rpc_credops	unix_credops;
33
34static struct rpc_auth *
35unx_create(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
36{
37	dprintk("RPC:       creating UNIX authenticator for client %p\n",
38			clnt);
39	atomic_inc(&unix_auth.au_count);
40	return &unix_auth;
41}
42
43static void
44unx_destroy(struct rpc_auth *auth)
45{
46	dprintk("RPC:       destroying UNIX authenticator %p\n", auth);
47	rpcauth_clear_credcache(auth->au_credcache);
48}
49
50/*
51 * Lookup AUTH_UNIX creds for current process
52 */
53static struct rpc_cred *
54unx_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
55{
56	return rpcauth_lookup_credcache(auth, acred, flags);
57}
58
59static struct rpc_cred *
60unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
61{
62	struct unx_cred	*cred;
63	unsigned int groups = 0;
64	unsigned int i;
65
66	dprintk("RPC:       allocating UNIX cred for uid %d gid %d\n",
67			acred->uid, acred->gid);
68
69	if (!(cred = kmalloc(sizeof(*cred), GFP_NOFS)))
70		return ERR_PTR(-ENOMEM);
71
72	rpcauth_init_cred(&cred->uc_base, acred, auth, &unix_credops);
73	cred->uc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
74
75	if (acred->group_info != NULL)
76		groups = acred->group_info->ngroups;
77	if (groups > NFS_NGROUPS)
78		groups = NFS_NGROUPS;
79
80	cred->uc_gid = acred->gid;
81	for (i = 0; i < groups; i++)
82		cred->uc_gids[i] = GROUP_AT(acred->group_info, i);
83	if (i < NFS_NGROUPS)
84		cred->uc_gids[i] = NOGROUP;
85
86	return &cred->uc_base;
87}
88
89static void
90unx_free_cred(struct unx_cred *unx_cred)
91{
92	dprintk("RPC:       unx_free_cred %p\n", unx_cred);
93	kfree(unx_cred);
94}
95
96static void
97unx_free_cred_callback(struct rcu_head *head)
98{
99	struct unx_cred *unx_cred = container_of(head, struct unx_cred, uc_base.cr_rcu);
100	unx_free_cred(unx_cred);
101}
102
103static void
104unx_destroy_cred(struct rpc_cred *cred)
105{
106	call_rcu(&cred->cr_rcu, unx_free_cred_callback);
107}
108
109/*
110 * Match credentials against current process creds.
111 * The root_override argument takes care of cases where the caller may
112 * request root creds (e.g. for NFS swapping).
113 */
114static int
115unx_match(struct auth_cred *acred, struct rpc_cred *rcred, int flags)
116{
117	struct unx_cred	*cred = container_of(rcred, struct unx_cred, uc_base);
118	unsigned int groups = 0;
119	unsigned int i;
120
121
122	if (cred->uc_uid != acred->uid || cred->uc_gid != acred->gid)
123		return 0;
124
125	if (acred->group_info != NULL)
126		groups = acred->group_info->ngroups;
127	if (groups > NFS_NGROUPS)
128		groups = NFS_NGROUPS;
129	for (i = 0; i < groups ; i++)
130		if (cred->uc_gids[i] != GROUP_AT(acred->group_info, i))
131			return 0;
132	return 1;
133}
134
135/*
136 * Marshal credentials.
137 * Maybe we should keep a cached credential for performance reasons.
138 */
139static __be32 *
140unx_marshal(struct rpc_task *task, __be32 *p)
141{
142	struct rpc_clnt	*clnt = task->tk_client;
143	struct unx_cred	*cred = container_of(task->tk_rqstp->rq_cred, struct unx_cred, uc_base);
144	__be32		*base, *hold;
145	int		i;
146
147	*p++ = htonl(RPC_AUTH_UNIX);
148	base = p++;
149	*p++ = htonl(jiffies/HZ);
150
151	/*
152	 * Copy the UTS nodename captured when the client was created.
153	 */
154	p = xdr_encode_array(p, clnt->cl_nodename, clnt->cl_nodelen);
155
156	*p++ = htonl((u32) cred->uc_uid);
157	*p++ = htonl((u32) cred->uc_gid);
158	hold = p++;
159	for (i = 0; i < 16 && cred->uc_gids[i] != (gid_t) NOGROUP; i++)
160		*p++ = htonl((u32) cred->uc_gids[i]);
161	*hold = htonl(p - hold - 1);		/* gid array length */
162	*base = htonl((p - base - 1) << 2);	/* cred length */
163
164	*p++ = htonl(RPC_AUTH_NULL);
165	*p++ = htonl(0);
166
167	return p;
168}
169
170/*
171 * Refresh credentials. This is a no-op for AUTH_UNIX
172 */
173static int
174unx_refresh(struct rpc_task *task)
175{
176	set_bit(RPCAUTH_CRED_UPTODATE, &task->tk_rqstp->rq_cred->cr_flags);
177	return 0;
178}
179
180static __be32 *
181unx_validate(struct rpc_task *task, __be32 *p)
182{
183	rpc_authflavor_t	flavor;
184	u32			size;
185
186	flavor = ntohl(*p++);
187	if (flavor != RPC_AUTH_NULL &&
188	    flavor != RPC_AUTH_UNIX &&
189	    flavor != RPC_AUTH_SHORT) {
190		printk("RPC: bad verf flavor: %u\n", flavor);
191		return NULL;
192	}
193
194	size = ntohl(*p++);
195	if (size > RPC_MAX_AUTH_SIZE) {
196		printk("RPC: giant verf size: %u\n", size);
197		return NULL;
198	}
199	task->tk_rqstp->rq_cred->cr_auth->au_rslack = (size >> 2) + 2;
200	p += (size >> 2);
201
202	return p;
203}
204
205int __init rpc_init_authunix(void)
206{
207	return rpcauth_init_credcache(&unix_auth);
208}
209
210void rpc_destroy_authunix(void)
211{
212	rpcauth_destroy_credcache(&unix_auth);
213}
214
215const struct rpc_authops authunix_ops = {
216	.owner		= THIS_MODULE,
217	.au_flavor	= RPC_AUTH_UNIX,
218	.au_name	= "UNIX",
219	.create		= unx_create,
220	.destroy	= unx_destroy,
221	.lookup_cred	= unx_lookup_cred,
222	.crcreate	= unx_create_cred,
223};
224
225static
226struct rpc_auth		unix_auth = {
227	.au_cslack	= UNX_WRITESLACK,
228	.au_rslack	= 2,			/* assume AUTH_NULL verf */
229	.au_ops		= &authunix_ops,
230	.au_flavor	= RPC_AUTH_UNIX,
231	.au_count	= ATOMIC_INIT(0),
232};
233
234static
235const struct rpc_credops unix_credops = {
236	.cr_name	= "AUTH_UNIX",
237	.crdestroy	= unx_destroy_cred,
238	.crbind		= rpcauth_generic_bind_cred,
239	.crmatch	= unx_match,
240	.crmarshal	= unx_marshal,
241	.crrefresh	= unx_refresh,
242	.crvalidate	= unx_validate,
243};
244