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         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  */
  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,
 100                         from_kuid(&init_user_ns, acred->uid),
 101                         from_kgid(&init_user_ns, 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 static int
 130 machine_cred_match(struct auth_cred *acred, struct generic_cred *gcred, int flags)
 131 {
 132         if (!gcred->acred.machine_cred ||
 133             gcred->acred.principal != acred->principal ||
 134             !uid_eq(gcred->acred.uid, acred->uid) ||
 135             !gid_eq(gcred->acred.gid, acred->gid))
 136                 return 0;
 137         return 1;
 138 }
 139
 140 /*
 141  * Match credentials against current process creds.
 142  */
 143 static int
 144 generic_match(struct auth_cred *acred, struct rpc_cred *cred, int flags)
 145 {
 146         struct generic_cred *gcred = container_of(cred, struct generic_cred, gc_base);
 147         int i;
 148
 149         if (acred->machine_cred)
 150                 return machine_cred_match(acred, gcred, flags);
 151
 152         if (!uid_eq(gcred->acred.uid, acred->uid) ||
 153             !gid_eq(gcred->acred.gid, acred->gid) ||
 154             gcred->acred.machine_cred != 0)
 155                 goto out_nomatch;
 156
 157         /* Optimisation in the case where pointers are identical... */
 158         if (gcred->acred.group_info == acred->group_info)
 159                 goto out_match;
 160
 161         /* Slow path... */
 162         if (gcred->acred.group_info->ngroups != acred->group_info->ngroups)
 163                 goto out_nomatch;
 164         for (i = 0; i < gcred->acred.group_info->ngroups; i++) {
 165                 if (!gid_eq(GROUP_AT(gcred->acred.group_info, i),
 166                                 GROUP_AT(acred->group_info, i)))
 167                         goto out_nomatch;
 168         }
 169 out_match:
 170         return 1;
 171 out_nomatch:
 172         return 0;
 173 }
 174
 175 int __init rpc_init_generic_auth(void)
 176 {
 177         return rpcauth_init_credcache(&generic_auth);
 178 }
 179
 180 void rpc_destroy_generic_auth(void)
 181 {
 182         rpcauth_destroy_credcache(&generic_auth);
 183 }
 184
 185 static const struct rpc_authops generic_auth_ops = {
 186         .owner = THIS_MODULE,
 187         .au_name = "Generic",
 188         .lookup_cred = generic_lookup_cred,
 189         .crcreate = generic_create_cred,
 190 };
 191
 192 static struct rpc_auth generic_auth = {
 193         .au_ops = &generic_auth_ops,
 194         .au_count = ATOMIC_INIT(0),
 195 };
 196
 197 static const struct rpc_credops generic_credops = {
 198         .cr_name = "Generic cred",
 199         .crdestroy = generic_destroy_cred,
 200         .crbind = generic_bind_cred,
 201         .crmatch = generic_match,
 202 };