net/sunrpc/auth_generic.c

   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         ((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 struct rpc_cred_cache generic_cred_cache;
  31 static const struct rpc_credops generic_credops;
  32
  33 /*
  34  * Public call interface
  35  */
  36 struct rpc_cred *rpc_lookup_cred(void)
  37 {
  38         return rpcauth_lookupcred(&generic_auth, 0);
  39 }
  40 EXPORT_SYMBOL_GPL(rpc_lookup_cred);
  41
  42 /*
  43  * Public call interface for looking up machine creds.
  44  */
  45 struct rpc_cred *rpc_lookup_machine_cred(void)
  46 {
  47         struct auth_cred acred = {
  48                 .uid = RPC_MACHINE_CRED_USERID,
  49                 .gid = RPC_MACHINE_CRED_GROUPID,
  50                 .machine_cred = 1,
  51         };
  52
  53         dprintk("RPC:       looking up machine cred\n");
  54         return generic_auth.au_ops->lookup_cred(&generic_auth, &acred, 0);
  55 }
  56 EXPORT_SYMBOL_GPL(rpc_lookup_machine_cred);
  57
  58 static void
  59 generic_bind_cred(struct rpc_task *task, struct rpc_cred *cred, int lookupflags)
  60 {
  61         struct rpc_auth *auth = task->tk_client->cl_auth;
  62         struct auth_cred *acred = &container_of(cred, struct generic_cred, gc_base)->acred;
  63         struct rpc_cred *ret;
  64
  65         ret = auth->au_ops->lookup_cred(auth, acred, lookupflags);
  66         if (!IS_ERR(ret))
  67                 task->tk_msg.rpc_cred = ret;
  68         else
  69                 task->tk_status = PTR_ERR(ret);
  70 }
  71
  72 /*
  73  * Lookup generic creds for current process
  74  */
  75 static struct rpc_cred *
  76 generic_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  77 {
  78         return rpcauth_lookup_credcache(&generic_auth, acred, flags);
  79 }
  80
  81 static struct rpc_cred *
  82 generic_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  83 {
  84         struct generic_cred *gcred;
  85
  86         gcred = kmalloc(sizeof(*gcred), GFP_KERNEL);
  87         if (gcred == NULL)
  88                 return ERR_PTR(-ENOMEM);
  89
  90         rpcauth_init_cred(&gcred->gc_base, acred, &generic_auth, &generic_credops);
  91         gcred->gc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
  92
  93         gcred->acred.uid = acred->uid;
  94         gcred->acred.gid = acred->gid;
  95         gcred->acred.group_info = acred->group_info;
  96         if (gcred->acred.group_info != NULL)
  97                 get_group_info(gcred->acred.group_info);
  98         gcred->acred.machine_cred = acred->machine_cred;
  99
 100         dprintk("RPC:       allocated %s cred %p for uid %d gid %d\n",
 101                         gcred->acred.machine_cred ? "machine" : "generic",
 102                         gcred, acred->uid, acred->gid);
 103         return &gcred->gc_base;
 104 }
 105
 106 static void
 107 generic_free_cred(struct rpc_cred *cred)
 108 {
 109         struct generic_cred *gcred = container_of(cred, struct generic_cred, gc_base);
 110
 111         dprintk("RPC:       generic_free_cred %p\n", gcred);
 112         if (gcred->acred.group_info != NULL)
 113                 put_group_info(gcred->acred.group_info);
 114         kfree(gcred);
 115 }
 116
 117 static void
 118 generic_free_cred_callback(struct rcu_head *head)
 119 {
 120         struct rpc_cred *cred = container_of(head, struct rpc_cred, cr_rcu);
 121         generic_free_cred(cred);
 122 }
 123
 124 static void
 125 generic_destroy_cred(struct rpc_cred *cred)
 126 {
 127         call_rcu(&cred->cr_rcu, generic_free_cred_callback);
 128 }
 129
 130 /*
 131  * Match credentials against current process creds.
 132  */
 133 static int
 134 generic_match(struct auth_cred *acred, struct rpc_cred *cred, int flags)
 135 {
 136         struct generic_cred *gcred = container_of(cred, struct generic_cred, gc_base);
 137         int i;
 138
 139         if (gcred->acred.uid != acred->uid ||
 140             gcred->acred.gid != acred->gid ||
 141             gcred->acred.machine_cred != acred->machine_cred)
 142                 goto out_nomatch;
 143
 144         /* Optimisation in the case where pointers are identical... */
 145         if (gcred->acred.group_info == acred->group_info)
 146                 goto out_match;
 147
 148         /* Slow path... */
 149         if (gcred->acred.group_info->ngroups != acred->group_info->ngroups)
 150                 goto out_nomatch;
 151         for (i = 0; i < gcred->acred.group_info->ngroups; i++) {
 152                 if (GROUP_AT(gcred->acred.group_info, i) !=
 153                                 GROUP_AT(acred->group_info, i))
 154                         goto out_nomatch;
 155         }
 156 out_match:
 157         return 1;
 158 out_nomatch:
 159         return 0;
 160 }
 161
 162 void __init rpc_init_generic_auth(void)
 163 {
 164         spin_lock_init(&generic_cred_cache.lock);
 165 }
 166
 167 void __exit rpc_destroy_generic_auth(void)
 168 {
 169         rpcauth_clear_credcache(&generic_cred_cache);
 170 }
 171
 172 static struct rpc_cred_cache generic_cred_cache = {
 173         {{ NULL, },},
 174 };
 175
 176 static const struct rpc_authops generic_auth_ops = {
 177         .owner = THIS_MODULE,
 178         .au_name = "Generic",
 179         .lookup_cred = generic_lookup_cred,
 180         .crcreate = generic_create_cred,
 181 };
 182
 183 static struct rpc_auth generic_auth = {
 184         .au_ops = &generic_auth_ops,
 185         .au_count = ATOMIC_INIT(0),
 186         .au_credcache = &generic_cred_cache,
 187 };
 188
 189 static const struct rpc_credops generic_credops = {
 190         .cr_name = "Generic cred",
 191         .crdestroy = generic_destroy_cred,
 192         .crbind = generic_bind_cred,
 193         .crmatch = generic_match,
 194 };