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/types.h>
   9 #include <linux/module.h>
  10 #include <linux/sched.h>
  11 #include <linux/sunrpc/auth.h>
  12 #include <linux/sunrpc/clnt.h>
  13 #include <linux/sunrpc/debug.h>
  14 #include <linux/sunrpc/sched.h>
  15
  16 #ifdef RPC_DEBUG
  17 # define RPCDBG_FACILITY        RPCDBG_AUTH
  18 #endif
  19
  20 #define RPC_MACHINE_CRED_USERID         ((uid_t)0)
  21 #define RPC_MACHINE_CRED_GROUPID        ((gid_t)0)
  22
  23 struct generic_cred {
  24         struct rpc_cred gc_base;
  25         struct auth_cred acred;
  26 };
  27
  28 static struct rpc_auth generic_auth;
  29 static struct rpc_cred_cache generic_cred_cache;
  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 }
  39 EXPORT_SYMBOL_GPL(rpc_lookup_cred);
  40
  41 /*
  42  * Public call interface for looking up machine creds.
  43  */
  44 struct rpc_cred *rpc_lookup_machine_cred(void)
  45 {
  46         struct auth_cred acred = {
  47                 .uid = RPC_MACHINE_CRED_USERID,
  48                 .gid = RPC_MACHINE_CRED_GROUPID,
  49                 .machine_cred = 1,
  50         };
  51
  52         dprintk("RPC:       looking up machine cred\n");
  53         return generic_auth.au_ops->lookup_cred(&generic_auth, &acred, 0);
  54 }
  55 EXPORT_SYMBOL_GPL(rpc_lookup_machine_cred);
  56
  57 static void
  58 generic_bind_cred(struct rpc_task *task, struct rpc_cred *cred)
  59 {
  60         struct rpc_auth *auth = task->tk_client->cl_auth;
  61         struct auth_cred *acred = &container_of(cred, struct generic_cred, gc_base)->acred;
  62         struct rpc_cred *ret;
  63
  64         ret = auth->au_ops->lookup_cred(auth, acred, 0);
  65         if (!IS_ERR(ret))
  66                 task->tk_msg.rpc_cred = ret;
  67         else
  68                 task->tk_status = PTR_ERR(ret);
  69 }
  70
  71 /*
  72  * Lookup generic creds for current process
  73  */
  74 static struct rpc_cred *
  75 generic_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  76 {
  77         return rpcauth_lookup_credcache(&generic_auth, acred, flags);
  78 }
  79
  80 static struct rpc_cred *
  81 generic_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  82 {
  83         struct generic_cred *gcred;
  84
  85         gcred = kmalloc(sizeof(*gcred), GFP_KERNEL);
  86         if (gcred == NULL)
  87                 return ERR_PTR(-ENOMEM);
  88
  89         rpcauth_init_cred(&gcred->gc_base, acred, &generic_auth, &generic_credops);
  90         gcred->gc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
  91
  92         gcred->acred.uid = acred->uid;
  93         gcred->acred.gid = acred->gid;
  94         gcred->acred.group_info = acred->group_info;
  95         if (gcred->acred.group_info != NULL)
  96                 get_group_info(gcred->acred.group_info);
  97         gcred->acred.machine_cred = acred->machine_cred;
  98
  99         dprintk("RPC:       allocated %s cred %p for uid %d gid %d\n",
 100                         gcred->acred.machine_cred ? "machine" : "generic",
 101                         gcred, acred->uid, acred->gid);
 102         return &gcred->gc_base;
 103 }
 104
 105 static void
 106 generic_free_cred(struct rpc_cred *cred)
 107 {
 108         struct generic_cred *gcred = container_of(cred, struct generic_cred, gc_base);
 109
 110         dprintk("RPC:       generic_free_cred %p\n", gcred);
 111         if (gcred->acred.group_info != NULL)
 112                 put_group_info(gcred->acred.group_info);
 113         kfree(gcred);
 114 }
 115
 116 static void
 117 generic_free_cred_callback(struct rcu_head *head)
 118 {
 119         struct rpc_cred *cred = container_of(head, struct rpc_cred, cr_rcu);
 120         generic_free_cred(cred);
 121 }
 122
 123 static void
 124 generic_destroy_cred(struct rpc_cred *cred)
 125 {
 126         call_rcu(&cred->cr_rcu, generic_free_cred_callback);
 127 }
 128
 129 /*
 130  * Match credentials against current process creds.
 131  */
 132 static int
 133 generic_match(struct auth_cred *acred, struct rpc_cred *cred, int flags)
 134 {
 135         struct generic_cred *gcred = container_of(cred, struct generic_cred, gc_base);
 136         int i;
 137
 138         if (gcred->acred.uid != acred->uid ||
 139             gcred->acred.gid != acred->gid ||
 140             gcred->acred.machine_cred != acred->machine_cred)
 141                 goto out_nomatch;
 142
 143         /* Optimisation in the case where pointers are identical... */
 144         if (gcred->acred.group_info == acred->group_info)
 145                 goto out_match;
 146
 147         /* Slow path... */
 148         if (gcred->acred.group_info->ngroups != acred->group_info->ngroups)
 149                 goto out_nomatch;
 150         for (i = 0; i < gcred->acred.group_info->ngroups; i++) {
 151                 if (GROUP_AT(gcred->acred.group_info, i) !=
 152                                 GROUP_AT(acred->group_info, i))
 153                         goto out_nomatch;
 154         }
 155 out_match:
 156         return 1;
 157 out_nomatch:
 158         return 0;
 159 }
 160
 161 void __init rpc_init_generic_auth(void)
 162 {
 163         spin_lock_init(&generic_cred_cache.lock);
 164 }
 165
 166 void __exit rpc_destroy_generic_auth(void)
 167 {
 168         rpcauth_clear_credcache(&generic_cred_cache);
 169 }
 170
 171 static struct rpc_cred_cache generic_cred_cache = {
 172         {{ NULL, },},
 173 };
 174
 175 static const struct rpc_authops generic_auth_ops = {
 176         .owner = THIS_MODULE,
 177         .au_name = "Generic",
 178         .lookup_cred = generic_lookup_cred,
 179         .crcreate = generic_create_cred,
 180 };
 181
 182 static struct rpc_auth generic_auth = {
 183         .au_ops = &generic_auth_ops,
 184         .au_count = ATOMIC_INIT(0),
 185         .au_credcache = &generic_cred_cache,
 186 };
 187
 188 static const struct rpc_credops generic_credops = {
 189         .cr_name = "Generic cred",
 190         .crdestroy = generic_destroy_cred,
 191         .crbind = generic_bind_cred,
 192         .crmatch = generic_match,
 193 };