File: /usr/src/linux/net/sunrpc/auth_unix.c
1 /*
2 * linux/net/sunrpc/rpcauth_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/slab.h>
11 #include <linux/socket.h>
12 #include <linux/in.h>
13 #include <linux/sunrpc/clnt.h>
14 #include <linux/sunrpc/auth.h>
15
16 #define NFS_NGROUPS 16
17 struct unx_cred {
18 struct rpc_cred uc_base;
19 uid_t uc_fsuid;
20 gid_t uc_gid, uc_fsgid;
21 gid_t uc_gids[NFS_NGROUPS];
22 };
23 #define uc_uid uc_base.cr_uid
24 #define uc_count uc_base.cr_count
25 #define uc_flags uc_base.cr_flags
26 #define uc_expire uc_base.cr_expire
27
28 #define UNX_CRED_EXPIRE (60 * HZ)
29
30 #define UNX_WRITESLACK (21 + (UNX_MAXNODENAME >> 2))
31
32 #ifdef RPC_DEBUG
33 # define RPCDBG_FACILITY RPCDBG_AUTH
34 #endif
35
36 static struct rpc_credops unix_credops;
37
38 static struct rpc_auth *
39 unx_create(struct rpc_clnt *clnt)
40 {
41 struct rpc_auth *auth;
42
43 dprintk("RPC: creating UNIX authenticator for client %p\n", clnt);
44 if (!(auth = (struct rpc_auth *) rpc_allocate(0, sizeof(*auth))))
45 return NULL;
46 auth->au_cslack = UNX_WRITESLACK;
47 auth->au_rslack = 2; /* assume AUTH_NULL verf */
48 auth->au_expire = UNX_CRED_EXPIRE;
49 auth->au_ops = &authunix_ops;
50
51 rpcauth_init_credcache(auth);
52
53 return auth;
54 }
55
56 static void
57 unx_destroy(struct rpc_auth *auth)
58 {
59 dprintk("RPC: destroying UNIX authenticator %p\n", auth);
60 rpcauth_free_credcache(auth);
61 rpc_free(auth);
62 }
63
64 static struct rpc_cred *
65 unx_create_cred(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 current->uid, current->gid);
72
73 if (!(cred = (struct unx_cred *) rpc_allocate(flags, sizeof(*cred))))
74 return NULL;
75
76 atomic_set(&cred->uc_count, 0);
77 cred->uc_flags = RPCAUTH_CRED_UPTODATE;
78 if (flags & RPC_TASK_ROOTCREDS) {
79 cred->uc_uid = cred->uc_fsuid = 0;
80 cred->uc_gid = cred->uc_fsgid = 0;
81 cred->uc_gids[0] = NOGROUP;
82 } else {
83 int groups = current->ngroups;
84 if (groups > NFS_NGROUPS)
85 groups = NFS_NGROUPS;
86
87 cred->uc_uid = current->uid;
88 cred->uc_gid = current->gid;
89 cred->uc_fsuid = current->fsuid;
90 cred->uc_fsgid = current->fsgid;
91 for (i = 0; i < groups; i++)
92 cred->uc_gids[i] = (gid_t) current->groups[i];
93 if (i < NFS_NGROUPS)
94 cred->uc_gids[i] = NOGROUP;
95 }
96 cred->uc_base.cr_ops = &unix_credops;
97
98 return (struct rpc_cred *) cred;
99 }
100
101 struct rpc_cred *
102 authunix_fake_cred(struct rpc_task *task, uid_t uid, gid_t gid)
103 {
104 struct unx_cred *cred;
105
106 dprintk("RPC: allocating fake UNIX cred for uid %d gid %d\n",
107 uid, gid);
108
109 if (!(cred = (struct unx_cred *) rpc_malloc(task, sizeof(*cred))))
110 return NULL;
111
112 atomic_set(&cred->uc_count, 1);
113 cred->uc_flags = RPCAUTH_CRED_DEAD|RPCAUTH_CRED_UPTODATE;
114 cred->uc_uid = uid;
115 cred->uc_gid = gid;
116 cred->uc_fsuid = uid;
117 cred->uc_fsgid = gid;
118 cred->uc_gids[0] = (gid_t) NOGROUP;
119
120 return task->tk_msg.rpc_cred = (struct rpc_cred *) cred;
121 }
122
123 static void
124 unx_destroy_cred(struct rpc_cred *cred)
125 {
126 rpc_free(cred);
127 }
128
129 /*
130 * Match credentials against current process creds.
131 * The root_override argument takes care of cases where the caller may
132 * request root creds (e.g. for NFS swapping).
133 */
134 static int
135 unx_match(struct rpc_cred *rcred, int taskflags)
136 {
137 struct unx_cred *cred = (struct unx_cred *) rcred;
138 int i;
139
140 if (!(taskflags & RPC_TASK_ROOTCREDS)) {
141 int groups;
142
143 if (cred->uc_uid != current->uid
144 || cred->uc_gid != current->gid
145 || cred->uc_fsuid != current->fsuid
146 || cred->uc_fsgid != current->fsgid)
147 return 0;
148
149 groups = current->ngroups;
150 if (groups > NFS_NGROUPS)
151 groups = NFS_NGROUPS;
152 for (i = 0; i < groups ; i++)
153 if (cred->uc_gids[i] != (gid_t) current->groups[i])
154 return 0;
155 return 1;
156 }
157 return (cred->uc_uid == 0 && cred->uc_fsuid == 0
158 && cred->uc_gid == 0 && cred->uc_fsgid == 0
159 && cred->uc_gids[0] == (gid_t) NOGROUP);
160 }
161
162 /*
163 * Marshal credentials.
164 * Maybe we should keep a cached credential for performance reasons.
165 */
166 static u32 *
167 unx_marshal(struct rpc_task *task, u32 *p, int ruid)
168 {
169 struct rpc_clnt *clnt = task->tk_client;
170 struct unx_cred *cred = (struct unx_cred *) task->tk_msg.rpc_cred;
171 u32 *base, *hold;
172 int i, n;
173
174 *p++ = htonl(RPC_AUTH_UNIX);
175 base = p++;
176 *p++ = htonl(jiffies/HZ);
177
178 /*
179 * Copy the UTS nodename captured when the client was created.
180 */
181 n = clnt->cl_nodelen;
182 *p++ = htonl(n);
183 memcpy(p, clnt->cl_nodename, n);
184 p += (n + 3) >> 2;
185
186 /* Note: we don't use real uid if it involves raising priviledge */
187 if (ruid && cred->uc_uid != 0 && cred->uc_gid != 0) {
188 *p++ = htonl((u32) cred->uc_uid);
189 *p++ = htonl((u32) cred->uc_gid);
190 } else {
191 *p++ = htonl((u32) cred->uc_fsuid);
192 *p++ = htonl((u32) cred->uc_fsgid);
193 }
194 hold = p++;
195 for (i = 0; i < 16 && cred->uc_gids[i] != (gid_t) NOGROUP; i++)
196 *p++ = htonl((u32) cred->uc_gids[i]);
197 *hold = htonl(p - hold - 1); /* gid array length */
198 *base = htonl((p - base - 1) << 2); /* cred length */
199
200 *p++ = htonl(RPC_AUTH_NULL);
201 *p++ = htonl(0);
202
203 return p;
204 }
205
206 /*
207 * Refresh credentials. This is a no-op for AUTH_UNIX
208 */
209 static int
210 unx_refresh(struct rpc_task *task)
211 {
212 task->tk_msg.rpc_cred->cr_flags |= RPCAUTH_CRED_UPTODATE;
213 return task->tk_status = -EACCES;
214 }
215
216 static u32 *
217 unx_validate(struct rpc_task *task, u32 *p)
218 {
219 u32 n = ntohl(*p++);
220
221 if (n != RPC_AUTH_NULL && n != RPC_AUTH_UNIX && n != RPC_AUTH_SHORT) {
222 printk("RPC: bad verf flavor: %ld\n", (unsigned long) n);
223 return NULL;
224 }
225 if ((n = ntohl(*p++)) > 400) {
226 printk("RPC: giant verf size: %ld\n", (unsigned long) n);
227 return NULL;
228 }
229 task->tk_auth->au_rslack = (n >> 2) + 2;
230 p += (n >> 2);
231
232 return p;
233 }
234
235 struct rpc_authops authunix_ops = {
236 RPC_AUTH_UNIX,
237 #ifdef RPC_DEBUG
238 "UNIX",
239 #endif
240 unx_create,
241 unx_destroy,
242 unx_create_cred
243 };
244
245 static
246 struct rpc_credops unix_credops = {
247 unx_destroy_cred,
248 unx_match,
249 unx_marshal,
250 unx_refresh,
251 unx_validate
252 };
253