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