Linux Kernel  3.7.1
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
auth_generic.c
Go to the documentation of this file.
1 /*
2  * Generic RPC credential
3  *
4  * Copyright (C) 2008, Trond Myklebust <[email protected]>
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 ((uid_t)0)
22 #define RPC_MACHINE_CRED_GROUPID ((gid_t)0)
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  */
35 struct rpc_cred *rpc_lookup_cred(void)
36 {
37  return rpcauth_lookupcred(&generic_auth, 0);
38 }
40 
41 /*
42  * Public call interface for looking up machine creds.
43  */
44 struct rpc_cred *rpc_lookup_machine_cred(const char *service_name)
45 {
46  struct auth_cred acred = {
49  .principal = service_name,
50  .machine_cred = 1,
51  };
52 
53  dprintk("RPC: looking up machine cred for service %s\n",
54  service_name);
55  return generic_auth.au_ops->lookup_cred(&generic_auth, &acred, 0);
56 }
58 
59 static struct rpc_cred *generic_bind_cred(struct rpc_task *task,
60  struct rpc_cred *cred, int lookupflags)
61 {
62  struct rpc_auth *auth = task->tk_client->cl_auth;
63  struct auth_cred *acred = &container_of(cred, struct generic_cred, gc_base)->acred;
64 
65  return auth->au_ops->lookup_cred(auth, acred, lookupflags);
66 }
67 
68 /*
69  * Lookup generic creds for current process
70  */
71 static struct rpc_cred *
72 generic_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
73 {
74  return rpcauth_lookup_credcache(&generic_auth, acred, flags);
75 }
76 
77 static struct rpc_cred *
78 generic_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
79 {
80  struct generic_cred *gcred;
81 
82  gcred = kmalloc(sizeof(*gcred), GFP_KERNEL);
83  if (gcred == NULL)
84  return ERR_PTR(-ENOMEM);
85 
86  rpcauth_init_cred(&gcred->gc_base, acred, &generic_auth, &generic_credops);
87  gcred->gc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
88 
89  gcred->acred.uid = acred->uid;
90  gcred->acred.gid = acred->gid;
91  gcred->acred.group_info = acred->group_info;
92  if (gcred->acred.group_info != NULL)
93  get_group_info(gcred->acred.group_info);
94  gcred->acred.machine_cred = acred->machine_cred;
95  gcred->acred.principal = acred->principal;
96 
97  dprintk("RPC: allocated %s cred %p for uid %d gid %d\n",
98  gcred->acred.machine_cred ? "machine" : "generic",
99  gcred, acred->uid, acred->gid);
100  return &gcred->gc_base;
101 }
102 
103 static void
104 generic_free_cred(struct rpc_cred *cred)
105 {
106  struct generic_cred *gcred = container_of(cred, struct generic_cred, gc_base);
107 
108  dprintk("RPC: generic_free_cred %p\n", gcred);
109  if (gcred->acred.group_info != NULL)
110  put_group_info(gcred->acred.group_info);
111  kfree(gcred);
112 }
113 
114 static void
115 generic_free_cred_callback(struct rcu_head *head)
116 {
117  struct rpc_cred *cred = container_of(head, struct rpc_cred, cr_rcu);
118  generic_free_cred(cred);
119 }
120 
121 static void
122 generic_destroy_cred(struct rpc_cred *cred)
123 {
124  call_rcu(&cred->cr_rcu, generic_free_cred_callback);
125 }
126 
127 static int
128 machine_cred_match(struct auth_cred *acred, struct generic_cred *gcred, int flags)
129 {
130  if (!gcred->acred.machine_cred ||
131  gcred->acred.principal != acred->principal ||
132  gcred->acred.uid != acred->uid ||
133  gcred->acred.gid != acred->gid)
134  return 0;
135  return 1;
136 }
137 
138 /*
139  * Match credentials against current process creds.
140  */
141 static int
142 generic_match(struct auth_cred *acred, struct rpc_cred *cred, int flags)
143 {
144  struct generic_cred *gcred = container_of(cred, struct generic_cred, gc_base);
145  int i;
146 
147  if (acred->machine_cred)
148  return machine_cred_match(acred, gcred, flags);
149 
150  if (gcred->acred.uid != acred->uid ||
151  gcred->acred.gid != acred->gid ||
152  gcred->acred.machine_cred != 0)
153  goto out_nomatch;
154 
155  /* Optimisation in the case where pointers are identical... */
156  if (gcred->acred.group_info == acred->group_info)
157  goto out_match;
158 
159  /* Slow path... */
160  if (gcred->acred.group_info->ngroups != acred->group_info->ngroups)
161  goto out_nomatch;
162  for (i = 0; i < gcred->acred.group_info->ngroups; i++) {
163  if (!gid_eq(GROUP_AT(gcred->acred.group_info, i),
164  GROUP_AT(acred->group_info, i)))
165  goto out_nomatch;
166  }
167 out_match:
168  return 1;
169 out_nomatch:
170  return 0;
171 }
172 
174 {
175  return rpcauth_init_credcache(&generic_auth);
176 }
177 
179 {
180  rpcauth_destroy_credcache(&generic_auth);
181 }
182 
183 static const struct rpc_authops generic_auth_ops = {
184  .owner = THIS_MODULE,
185  .au_name = "Generic",
186  .lookup_cred = generic_lookup_cred,
187  .crcreate = generic_create_cred,
188 };
189 
190 static struct rpc_auth generic_auth = {
191  .au_ops = &generic_auth_ops,
192  .au_count = ATOMIC_INIT(0),
193 };
194 
195 static const struct rpc_credops generic_credops = {
196  .cr_name = "Generic cred",
197  .crdestroy = generic_destroy_cred,
198  .crbind = generic_bind_cred,
199  .crmatch = generic_match,
200 };