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 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(const char *service_name)
  45 {
  46         struct auth_cred acred = {
  47                 .uid = RPC_MACHINE_CRED_USERID,
  48                 .gid = RPC_MACHINE_CRED_GROUPID,
  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 }
  57 EXPORT_SYMBOL_GPL(rpc_lookup_machine_cred);
  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
 173 int __init rpc_init_generic_auth(void)
 174 {
 175         return rpcauth_init_credcache(&generic_auth);
 176 }
 177
 178 void rpc_destroy_generic_auth(void)
 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 };