1 /*
2 * Generic RPC credential
3 *
4 * Copyright (C) 2008, Trond Myklebust <Trond.Myklebust@netapp.com>
5 */
6
7 #include <linux/err.h>
8 #include <linux/slab.h>
9 #include <linux/types.h>
10 #include <linux/module.h>
11 #include <linux/sched.h>
12 #include <linux/sunrpc/auth.h>
13 #include <linux/sunrpc/clnt.h>
14 #include <linux/sunrpc/debug.h>
15 #include <linux/sunrpc/sched.h>
16
17 #ifdef RPC_DEBUG
18 # define RPCDBG_FACILITY RPCDBG_AUTH
19 #endif
20
21 #define RPC_MACHINE_CRED_USERID GLOBAL_ROOT_UID
22 #define RPC_MACHINE_CRED_GROUPID GLOBAL_ROOT_GID
23
24 struct generic_cred {
25 struct rpc_cred gc_base;
26 struct auth_cred acred;
27 };
28
29 static struct rpc_auth generic_auth;
30 static const struct rpc_credops generic_credops;
31
32 /*
33 * Public call interface
34 */
rpc_lookup_cred(void)35 struct rpc_cred *rpc_lookup_cred(void)
36 {
37 return rpcauth_lookupcred(&generic_auth, 0);
38 }
39 EXPORT_SYMBOL_GPL(rpc_lookup_cred);
40
rpc_lookup_cred_nonblock(void)41 struct rpc_cred *rpc_lookup_cred_nonblock(void)
42 {
43 return rpcauth_lookupcred(&generic_auth, RPCAUTH_LOOKUP_RCU);
44 }
45 EXPORT_SYMBOL_GPL(rpc_lookup_cred_nonblock);
46
47 /*
48 * Public call interface for looking up machine creds.
49 */
rpc_lookup_machine_cred(const char * service_name)50 struct rpc_cred *rpc_lookup_machine_cred(const char *service_name)
51 {
52 struct auth_cred acred = {
53 .uid = RPC_MACHINE_CRED_USERID,
54 .gid = RPC_MACHINE_CRED_GROUPID,
55 .principal = service_name,
56 .machine_cred = 1,
57 };
58
59 dprintk("RPC: looking up machine cred for service %s\n",
60 service_name);
61 return generic_auth.au_ops->lookup_cred(&generic_auth, &acred, 0);
62 }
63 EXPORT_SYMBOL_GPL(rpc_lookup_machine_cred);
64
generic_bind_cred(struct rpc_task * task,struct rpc_cred * cred,int lookupflags)65 static struct rpc_cred *generic_bind_cred(struct rpc_task *task,
66 struct rpc_cred *cred, int lookupflags)
67 {
68 struct rpc_auth *auth = task->tk_client->cl_auth;
69 struct auth_cred *acred = &container_of(cred, struct generic_cred, gc_base)->acred;
70
71 return auth->au_ops->lookup_cred(auth, acred, lookupflags);
72 }
73
74 /*
75 * Lookup generic creds for current process
76 */
77 static struct rpc_cred *
generic_lookup_cred(struct rpc_auth * auth,struct auth_cred * acred,int flags)78 generic_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
79 {
80 return rpcauth_lookup_credcache(&generic_auth, acred, flags);
81 }
82
83 static struct rpc_cred *
generic_create_cred(struct rpc_auth * auth,struct auth_cred * acred,int flags)84 generic_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
85 {
86 struct generic_cred *gcred;
87
88 gcred = kmalloc(sizeof(*gcred), GFP_KERNEL);
89 if (gcred == NULL)
90 return ERR_PTR(-ENOMEM);
91
92 rpcauth_init_cred(&gcred->gc_base, acred, &generic_auth, &generic_credops);
93 gcred->gc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
94
95 gcred->acred.uid = acred->uid;
96 gcred->acred.gid = acred->gid;
97 gcred->acred.group_info = acred->group_info;
98 gcred->acred.ac_flags = 0;
99 if (gcred->acred.group_info != NULL)
100 get_group_info(gcred->acred.group_info);
101 gcred->acred.machine_cred = acred->machine_cred;
102 gcred->acred.principal = acred->principal;
103
104 dprintk("RPC: allocated %s cred %p for uid %d gid %d\n",
105 gcred->acred.machine_cred ? "machine" : "generic",
106 gcred,
107 from_kuid(&init_user_ns, acred->uid),
108 from_kgid(&init_user_ns, acred->gid));
109 return &gcred->gc_base;
110 }
111
112 static void
generic_free_cred(struct rpc_cred * cred)113 generic_free_cred(struct rpc_cred *cred)
114 {
115 struct generic_cred *gcred = container_of(cred, struct generic_cred, gc_base);
116
117 dprintk("RPC: generic_free_cred %p\n", gcred);
118 if (gcred->acred.group_info != NULL)
119 put_group_info(gcred->acred.group_info);
120 kfree(gcred);
121 }
122
123 static void
generic_free_cred_callback(struct rcu_head * head)124 generic_free_cred_callback(struct rcu_head *head)
125 {
126 struct rpc_cred *cred = container_of(head, struct rpc_cred, cr_rcu);
127 generic_free_cred(cred);
128 }
129
130 static void
generic_destroy_cred(struct rpc_cred * cred)131 generic_destroy_cred(struct rpc_cred *cred)
132 {
133 call_rcu(&cred->cr_rcu, generic_free_cred_callback);
134 }
135
136 static int
machine_cred_match(struct auth_cred * acred,struct generic_cred * gcred,int flags)137 machine_cred_match(struct auth_cred *acred, struct generic_cred *gcred, int flags)
138 {
139 if (!gcred->acred.machine_cred ||
140 gcred->acred.principal != acred->principal ||
141 !uid_eq(gcred->acred.uid, acred->uid) ||
142 !gid_eq(gcred->acred.gid, acred->gid))
143 return 0;
144 return 1;
145 }
146
147 /*
148 * Match credentials against current process creds.
149 */
150 static int
generic_match(struct auth_cred * acred,struct rpc_cred * cred,int flags)151 generic_match(struct auth_cred *acred, struct rpc_cred *cred, int flags)
152 {
153 struct generic_cred *gcred = container_of(cred, struct generic_cred, gc_base);
154 int i;
155
156 if (acred->machine_cred)
157 return machine_cred_match(acred, gcred, flags);
158
159 if (!uid_eq(gcred->acred.uid, acred->uid) ||
160 !gid_eq(gcred->acred.gid, acred->gid) ||
161 gcred->acred.machine_cred != 0)
162 goto out_nomatch;
163
164 /* Optimisation in the case where pointers are identical... */
165 if (gcred->acred.group_info == acred->group_info)
166 goto out_match;
167
168 /* Slow path... */
169 if (gcred->acred.group_info->ngroups != acred->group_info->ngroups)
170 goto out_nomatch;
171 for (i = 0; i < gcred->acred.group_info->ngroups; i++) {
172 if (!gid_eq(GROUP_AT(gcred->acred.group_info, i),
173 GROUP_AT(acred->group_info, i)))
174 goto out_nomatch;
175 }
176 out_match:
177 return 1;
178 out_nomatch:
179 return 0;
180 }
181
rpc_init_generic_auth(void)182 int __init rpc_init_generic_auth(void)
183 {
184 return rpcauth_init_credcache(&generic_auth);
185 }
186
rpc_destroy_generic_auth(void)187 void rpc_destroy_generic_auth(void)
188 {
189 rpcauth_destroy_credcache(&generic_auth);
190 }
191
192 /*
193 * Test the the current time (now) against the underlying credential key expiry
194 * minus a timeout and setup notification.
195 *
196 * The normal case:
197 * If 'now' is before the key expiry minus RPC_KEY_EXPIRE_TIMEO, set
198 * the RPC_CRED_NOTIFY_TIMEOUT flag to setup the underlying credential
199 * rpc_credops crmatch routine to notify this generic cred when it's key
200 * expiration is within RPC_KEY_EXPIRE_TIMEO, and return 0.
201 *
202 * The error case:
203 * If the underlying cred lookup fails, return -EACCES.
204 *
205 * The 'almost' error case:
206 * If 'now' is within key expiry minus RPC_KEY_EXPIRE_TIMEO, but not within
207 * key expiry minus RPC_KEY_EXPIRE_FAIL, set the RPC_CRED_EXPIRE_SOON bit
208 * on the acred ac_flags and return 0.
209 */
210 static int
generic_key_timeout(struct rpc_auth * auth,struct rpc_cred * cred)211 generic_key_timeout(struct rpc_auth *auth, struct rpc_cred *cred)
212 {
213 struct auth_cred *acred = &container_of(cred, struct generic_cred,
214 gc_base)->acred;
215 struct rpc_cred *tcred;
216 int ret = 0;
217
218
219 /* Fast track for non crkey_timeout (no key) underlying credentials */
220 if (test_bit(RPC_CRED_NO_CRKEY_TIMEOUT, &acred->ac_flags))
221 return 0;
222
223 /* Fast track for the normal case */
224 if (test_bit(RPC_CRED_NOTIFY_TIMEOUT, &acred->ac_flags))
225 return 0;
226
227 /* lookup_cred either returns a valid referenced rpc_cred, or PTR_ERR */
228 tcred = auth->au_ops->lookup_cred(auth, acred, 0);
229 if (IS_ERR(tcred))
230 return -EACCES;
231
232 if (!tcred->cr_ops->crkey_timeout) {
233 set_bit(RPC_CRED_NO_CRKEY_TIMEOUT, &acred->ac_flags);
234 ret = 0;
235 goto out_put;
236 }
237
238 /* Test for the almost error case */
239 ret = tcred->cr_ops->crkey_timeout(tcred);
240 if (ret != 0) {
241 set_bit(RPC_CRED_KEY_EXPIRE_SOON, &acred->ac_flags);
242 ret = 0;
243 } else {
244 /* In case underlying cred key has been reset */
245 if (test_and_clear_bit(RPC_CRED_KEY_EXPIRE_SOON,
246 &acred->ac_flags))
247 dprintk("RPC: UID %d Credential key reset\n",
248 from_kuid(&init_user_ns, tcred->cr_uid));
249 /* set up fasttrack for the normal case */
250 set_bit(RPC_CRED_NOTIFY_TIMEOUT, &acred->ac_flags);
251 }
252
253 out_put:
254 put_rpccred(tcred);
255 return ret;
256 }
257
258 static const struct rpc_authops generic_auth_ops = {
259 .owner = THIS_MODULE,
260 .au_name = "Generic",
261 .lookup_cred = generic_lookup_cred,
262 .crcreate = generic_create_cred,
263 .key_timeout = generic_key_timeout,
264 };
265
266 static struct rpc_auth generic_auth = {
267 .au_ops = &generic_auth_ops,
268 .au_count = ATOMIC_INIT(0),
269 };
270
generic_key_to_expire(struct rpc_cred * cred)271 static bool generic_key_to_expire(struct rpc_cred *cred)
272 {
273 struct auth_cred *acred = &container_of(cred, struct generic_cred,
274 gc_base)->acred;
275 bool ret;
276
277 get_rpccred(cred);
278 ret = test_bit(RPC_CRED_KEY_EXPIRE_SOON, &acred->ac_flags);
279 put_rpccred(cred);
280
281 return ret;
282 }
283
284 static const struct rpc_credops generic_credops = {
285 .cr_name = "Generic cred",
286 .crdestroy = generic_destroy_cred,
287 .crbind = generic_bind_cred,
288 .crmatch = generic_match,
289 .crkey_to_expire = generic_key_to_expire,
290 };
291