linux/net/sunrpc/auth_generic.c
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   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
  24struct generic_cred {
  25        struct rpc_cred gc_base;
  26        struct auth_cred acred;
  27};
  28
  29static struct rpc_auth generic_auth;
  30static const struct rpc_credops generic_credops;
  31
  32/*
  33 * Public call interface
  34 */
  35struct rpc_cred *rpc_lookup_cred(void)
  36{
  37        return rpcauth_lookupcred(&generic_auth, 0);
  38}
  39EXPORT_SYMBOL_GPL(rpc_lookup_cred);
  40
  41/*
  42 * Public call interface for looking up machine creds.
  43 */
  44struct 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}
  57EXPORT_SYMBOL_GPL(rpc_lookup_machine_cred);
  58
  59static 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 */
  71static struct rpc_cred *
  72generic_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  73{
  74        return rpcauth_lookup_credcache(&generic_auth, acred, flags);
  75}
  76
  77static struct rpc_cred *
  78generic_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
 103static void
 104generic_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
 114static void
 115generic_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
 121static void
 122generic_destroy_cred(struct rpc_cred *cred)
 123{
 124        call_rcu(&cred->cr_rcu, generic_free_cred_callback);
 125}
 126
 127static int
 128machine_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 */
 141static int
 142generic_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        }
 167out_match:
 168        return 1;
 169out_nomatch:
 170        return 0;
 171}
 172
 173int __init rpc_init_generic_auth(void)
 174{
 175        return rpcauth_init_credcache(&generic_auth);
 176}
 177
 178void rpc_destroy_generic_auth(void)
 179{
 180        rpcauth_destroy_credcache(&generic_auth);
 181}
 182
 183static 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
 190static struct rpc_auth generic_auth = {
 191        .au_ops = &generic_auth_ops,
 192        .au_count = ATOMIC_INIT(0),
 193};
 194
 195static 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};
 201
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