Merge master.kernel.org:/home/rmk/linux-2.6-mmc
[linux-2.6] / net / sunrpc / auth_unix.c
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
17 struct 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
35 static struct rpc_auth          unix_auth;
36 static struct rpc_cred_cache    unix_cred_cache;
37 static struct rpc_credops       unix_credops;
38
39 static struct rpc_auth *
40 unx_create(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
41 {
42         dprintk("RPC: creating UNIX authenticator for client %p\n", clnt);
43         if (atomic_inc_return(&unix_auth.au_count) == 0)
44                 unix_cred_cache.nextgc = jiffies + (unix_cred_cache.expire >> 1);
45         return &unix_auth;
46 }
47
48 static void
49 unx_destroy(struct rpc_auth *auth)
50 {
51         dprintk("RPC: destroying UNIX authenticator %p\n", auth);
52         rpcauth_free_credcache(auth);
53 }
54
55 /*
56  * Lookup AUTH_UNIX creds for current process
57  */
58 static struct rpc_cred *
59 unx_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
60 {
61         return rpcauth_lookup_credcache(auth, acred, flags);
62 }
63
64 static struct rpc_cred *
65 unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
66 {
67         struct unx_cred *cred;
68         int             i;
69
70         dprintk("RPC:      allocating UNIX cred for uid %d gid %d\n",
71                                 acred->uid, acred->gid);
72
73         if (!(cred = kmalloc(sizeof(*cred), GFP_KERNEL)))
74                 return ERR_PTR(-ENOMEM);
75
76         atomic_set(&cred->uc_count, 1);
77         cred->uc_flags = RPCAUTH_CRED_UPTODATE;
78         if (flags & RPCAUTH_LOOKUP_ROOTCREDS) {
79                 cred->uc_uid = 0;
80                 cred->uc_gid = 0;
81                 cred->uc_gids[0] = NOGROUP;
82         } else {
83                 int groups = acred->group_info->ngroups;
84                 if (groups > NFS_NGROUPS)
85                         groups = NFS_NGROUPS;
86
87                 cred->uc_uid = acred->uid;
88                 cred->uc_gid = acred->gid;
89                 for (i = 0; i < groups; i++)
90                         cred->uc_gids[i] = GROUP_AT(acred->group_info, i);
91                 if (i < NFS_NGROUPS)
92                   cred->uc_gids[i] = NOGROUP;
93         }
94         cred->uc_base.cr_ops = &unix_credops;
95
96         return (struct rpc_cred *) cred;
97 }
98
99 static void
100 unx_destroy_cred(struct rpc_cred *cred)
101 {
102         kfree(cred);
103 }
104
105 /*
106  * Match credentials against current process creds.
107  * The root_override argument takes care of cases where the caller may
108  * request root creds (e.g. for NFS swapping).
109  */
110 static int
111 unx_match(struct auth_cred *acred, struct rpc_cred *rcred, int flags)
112 {
113         struct unx_cred *cred = (struct unx_cred *) rcred;
114         int             i;
115
116         if (!(flags & RPCAUTH_LOOKUP_ROOTCREDS)) {
117                 int groups;
118
119                 if (cred->uc_uid != acred->uid
120                  || cred->uc_gid != acred->gid)
121                         return 0;
122
123                 groups = acred->group_info->ngroups;
124                 if (groups > NFS_NGROUPS)
125                         groups = NFS_NGROUPS;
126                 for (i = 0; i < groups ; i++)
127                         if (cred->uc_gids[i] != GROUP_AT(acred->group_info, i))
128                                 return 0;
129                 return 1;
130         }
131         return (cred->uc_uid == 0
132              && cred->uc_gid == 0
133              && cred->uc_gids[0] == (gid_t) NOGROUP);
134 }
135
136 /*
137  * Marshal credentials.
138  * Maybe we should keep a cached credential for performance reasons.
139  */
140 static u32 *
141 unx_marshal(struct rpc_task *task, u32 *p)
142 {
143         struct rpc_clnt *clnt = task->tk_client;
144         struct unx_cred *cred = (struct unx_cred *) task->tk_msg.rpc_cred;
145         u32             *base, *hold;
146         int             i;
147
148         *p++ = htonl(RPC_AUTH_UNIX);
149         base = p++;
150         *p++ = htonl(jiffies/HZ);
151
152         /*
153          * Copy the UTS nodename captured when the client was created.
154          */
155         p = xdr_encode_array(p, clnt->cl_nodename, clnt->cl_nodelen);
156
157         *p++ = htonl((u32) cred->uc_uid);
158         *p++ = htonl((u32) cred->uc_gid);
159         hold = p++;
160         for (i = 0; i < 16 && cred->uc_gids[i] != (gid_t) NOGROUP; i++)
161                 *p++ = htonl((u32) cred->uc_gids[i]);
162         *hold = htonl(p - hold - 1);            /* gid array length */
163         *base = htonl((p - base - 1) << 2);     /* cred length */
164
165         *p++ = htonl(RPC_AUTH_NULL);
166         *p++ = htonl(0);
167
168         return p;
169 }
170
171 /*
172  * Refresh credentials. This is a no-op for AUTH_UNIX
173  */
174 static int
175 unx_refresh(struct rpc_task *task)
176 {
177         task->tk_msg.rpc_cred->cr_flags |= RPCAUTH_CRED_UPTODATE;
178         return 0;
179 }
180
181 static u32 *
182 unx_validate(struct rpc_task *task, u32 *p)
183 {
184         rpc_authflavor_t        flavor;
185         u32                     size;
186
187         flavor = ntohl(*p++);
188         if (flavor != RPC_AUTH_NULL &&
189             flavor != RPC_AUTH_UNIX &&
190             flavor != RPC_AUTH_SHORT) {
191                 printk("RPC: bad verf flavor: %u\n", flavor);
192                 return NULL;
193         }
194
195         size = ntohl(*p++);
196         if (size > RPC_MAX_AUTH_SIZE) {
197                 printk("RPC: giant verf size: %u\n", size);
198                 return NULL;
199         }
200         task->tk_auth->au_rslack = (size >> 2) + 2;
201         p += (size >> 2);
202
203         return p;
204 }
205
206 struct rpc_authops      authunix_ops = {
207         .owner          = THIS_MODULE,
208         .au_flavor      = RPC_AUTH_UNIX,
209 #ifdef RPC_DEBUG
210         .au_name        = "UNIX",
211 #endif
212         .create         = unx_create,
213         .destroy        = unx_destroy,
214         .lookup_cred    = unx_lookup_cred,
215         .crcreate       = unx_create_cred,
216 };
217
218 static
219 struct rpc_cred_cache   unix_cred_cache = {
220         .expire         = UNX_CRED_EXPIRE,
221 };
222
223 static
224 struct rpc_auth         unix_auth = {
225         .au_cslack      = UNX_WRITESLACK,
226         .au_rslack      = 2,                    /* assume AUTH_NULL verf */
227         .au_ops         = &authunix_ops,
228         .au_count       = ATOMIC_INIT(0),
229         .au_credcache   = &unix_cred_cache,
230 };
231
232 static
233 struct rpc_credops      unix_credops = {
234         .cr_name        = "AUTH_UNIX",
235         .crdestroy      = unx_destroy_cred,
236         .crmatch        = unx_match,
237         .crmarshal      = unx_marshal,
238         .crrefresh      = unx_refresh,
239         .crvalidate     = unx_validate,
240 };