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
24 #define UNX_WRITESLACK (21 + (UNX_MAXNODENAME >> 2))
25
26 #ifdef RPC_DEBUG
27 # define RPCDBG_FACILITY RPCDBG_AUTH
28 #endif
29
30 static struct rpc_auth unix_auth;
31 static struct rpc_cred_cache unix_cred_cache;
32 static const struct rpc_credops unix_credops;
33
34 static struct rpc_auth *
35 unx_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
43 static void
44 unx_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 */
53 static struct rpc_cred *
54 unx_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
55 {
56 return rpcauth_lookup_credcache(auth, acred, flags);
57 }
58
59 static struct rpc_cred *
60 unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
61 {
62 struct unx_cred *cred;
63 int i;
64
65 dprintk("RPC: allocating UNIX cred for uid %d gid %d\n",
66 acred->uid, acred->gid);
67
68 if (!(cred = kmalloc(sizeof(*cred), GFP_KERNEL)))
69 return ERR_PTR(-ENOMEM);
70
71 rpcauth_init_cred(&cred->uc_base, acred, auth, &unix_credops);
72 cred->uc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
73 if (flags & RPCAUTH_LOOKUP_ROOTCREDS) {
74 cred->uc_uid = 0;
75 cred->uc_gid = 0;
76 cred->uc_gids[0] = NOGROUP;
77 } else {
78 int groups = acred->group_info->ngroups;
79 if (groups > NFS_NGROUPS)
80 groups = NFS_NGROUPS;
81
82 cred->uc_gid = acred->gid;
83 for (i = 0; i < groups; i++)
84 cred->uc_gids[i] = GROUP_AT(acred->group_info, i);
85 if (i < NFS_NGROUPS)
86 cred->uc_gids[i] = NOGROUP;
87 }
88
89 return &cred->uc_base;
90 }
91
92 static void
93 unx_free_cred(struct unx_cred *unx_cred)
94 {
95 dprintk("RPC: unx_free_cred %p\n", unx_cred);
96 kfree(unx_cred);
97 }
98
99 static void
100 unx_free_cred_callback(struct rcu_head *head)
101 {
102 struct unx_cred *unx_cred = container_of(head, struct unx_cred, uc_base.cr_rcu);
103 unx_free_cred(unx_cred);
104 }
105
106 static void
107 unx_destroy_cred(struct rpc_cred *cred)
108 {
109 call_rcu(&cred->cr_rcu, unx_free_cred_callback);
110 }
111
112 /*
113 * Match credentials against current process creds.
114 * The root_override argument takes care of cases where the caller may
115 * request root creds (e.g. for NFS swapping).
116 */
117 static int
118 unx_match(struct auth_cred *acred, struct rpc_cred *rcred, int flags)
119 {
120 struct unx_cred *cred = container_of(rcred, struct unx_cred, uc_base);
121 int i;
122
123 if (!(flags & RPCAUTH_LOOKUP_ROOTCREDS)) {
124 int groups;
125
126 if (cred->uc_uid != acred->uid
127 || cred->uc_gid != acred->gid)
128 return 0;
129
130 groups = acred->group_info->ngroups;
131 if (groups > NFS_NGROUPS)
132 groups = NFS_NGROUPS;
133 for (i = 0; i < groups ; i++)
134 if (cred->uc_gids[i] != GROUP_AT(acred->group_info, i))
135 return 0;
136 return 1;
137 }
138 return (cred->uc_uid == 0
139 && cred->uc_gid == 0
140 && cred->uc_gids[0] == (gid_t) NOGROUP);
141 }
142
143 /*
144 * Marshal credentials.
145 * Maybe we should keep a cached credential for performance reasons.
146 */
147 static __be32 *
148 unx_marshal(struct rpc_task *task, __be32 *p)
149 {
150 struct rpc_clnt *clnt = task->tk_client;
151 struct unx_cred *cred = container_of(task->tk_msg.rpc_cred, struct unx_cred, uc_base);
152 __be32 *base, *hold;
153 int i;
154
155 *p++ = htonl(RPC_AUTH_UNIX);
156 base = p++;
157 *p++ = htonl(jiffies/HZ);
158
159 /*
160 * Copy the UTS nodename captured when the client was created.
161 */
162 p = xdr_encode_array(p, clnt->cl_nodename, clnt->cl_nodelen);
163
164 *p++ = htonl((u32) cred->uc_uid);
165 *p++ = htonl((u32) cred->uc_gid);
166 hold = p++;
167 for (i = 0; i < 16 && cred->uc_gids[i] != (gid_t) NOGROUP; i++)
168 *p++ = htonl((u32) cred->uc_gids[i]);
169 *hold = htonl(p - hold - 1); /* gid array length */
170 *base = htonl((p - base - 1) << 2); /* cred length */
171
172 *p++ = htonl(RPC_AUTH_NULL);
173 *p++ = htonl(0);
174
175 return p;
176 }
177
178 /*
179 * Refresh credentials. This is a no-op for AUTH_UNIX
180 */
181 static int
182 unx_refresh(struct rpc_task *task)
183 {
184 set_bit(RPCAUTH_CRED_UPTODATE, &task->tk_msg.rpc_cred->cr_flags);
185 return 0;
186 }
187
188 static __be32 *
189 unx_validate(struct rpc_task *task, __be32 *p)
190 {
191 rpc_authflavor_t flavor;
192 u32 size;
193
194 flavor = ntohl(*p++);
195 if (flavor != RPC_AUTH_NULL &&
196 flavor != RPC_AUTH_UNIX &&
197 flavor != RPC_AUTH_SHORT) {
198 printk("RPC: bad verf flavor: %u\n", flavor);
199 return NULL;
200 }
201
202 size = ntohl(*p++);
203 if (size > RPC_MAX_AUTH_SIZE) {
204 printk("RPC: giant verf size: %u\n", size);
205 return NULL;
206 }
207 task->tk_msg.rpc_cred->cr_auth->au_rslack = (size >> 2) + 2;
208 p += (size >> 2);
209
210 return p;
211 }
212
213 void __init rpc_init_authunix(void)
214 {
215 spin_lock_init(&unix_cred_cache.lock);
216 }
217
218 const struct rpc_authops authunix_ops = {
219 .owner = THIS_MODULE,
220 .au_flavor = RPC_AUTH_UNIX,
221 #ifdef RPC_DEBUG
222 .au_name = "UNIX",
223 #endif
224 .create = unx_create,
225 .destroy = unx_destroy,
226 .lookup_cred = unx_lookup_cred,
227 .crcreate = unx_create_cred,
228 };
229
230 static
231 struct rpc_cred_cache unix_cred_cache = {
232 };
233
234 static
235 struct rpc_auth unix_auth = {
236 .au_cslack = UNX_WRITESLACK,
237 .au_rslack = 2, /* assume AUTH_NULL verf */
238 .au_ops = &authunix_ops,
239 .au_flavor = RPC_AUTH_UNIX,
240 .au_count = ATOMIC_INIT(0),
241 .au_credcache = &unix_cred_cache,
242 };
243
244 static
245 const struct rpc_credops unix_credops = {
246 .cr_name = "AUTH_UNIX",
247 .crdestroy = unx_destroy_cred,
248 .crmatch = unx_match,
249 .crmarshal = unx_marshal,
250 .crrefresh = unx_refresh,
251 .crvalidate = unx_validate,
252 };
253
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