linux/net/sunrpc/auth_unix.c
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   1/*
   2 * linux/net/sunrpc/auth_unix.c
   3 *
   4 * UNIX-style authentication; no AUTH_SHORT support
   5 *
   6 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
   7 */
   8
   9#include <linux/types.h>
  10#include <linux/sched.h>
  11#include <linux/module.h>
  12#include <linux/sunrpc/clnt.h>
  13#include <linux/sunrpc/auth.h>
  14
  15#define NFS_NGROUPS     16
  16
  17struct unx_cred {
  18        struct rpc_cred         uc_base;
  19        gid_t                   uc_gid;
  20        gid_t                   uc_gids[NFS_NGROUPS];
  21};
  22#define uc_uid                  uc_base.cr_uid
  23
  24#define UNX_WRITESLACK          (21 + (UNX_MAXNODENAME >> 2))
  25
  26#ifdef RPC_DEBUG
  27# define RPCDBG_FACILITY        RPCDBG_AUTH
  28#endif
  29
  30static struct rpc_auth          unix_auth;
  31static struct rpc_cred_cache    unix_cred_cache;
  32static const struct rpc_credops unix_credops;
  33
  34static struct rpc_auth *
  35unx_create(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
  36{
  37        dprintk("RPC:       creating UNIX authenticator for client %p\n",
  38                        clnt);
  39        atomic_inc(&unix_auth.au_count);
  40        return &unix_auth;
  41}
  42
  43static void
  44unx_destroy(struct rpc_auth *auth)
  45{
  46        dprintk("RPC:       destroying UNIX authenticator %p\n", auth);
  47        rpcauth_clear_credcache(auth->au_credcache);
  48}
  49
  50/*
  51 * Lookup AUTH_UNIX creds for current process
  52 */
  53static struct rpc_cred *
  54unx_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  55{
  56        return rpcauth_lookup_credcache(auth, acred, flags);
  57}
  58
  59static struct rpc_cred *
  60unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  61{
  62        struct unx_cred *cred;
  63        unsigned int groups = 0;
  64        unsigned int i;
  65
  66        dprintk("RPC:       allocating UNIX cred for uid %d gid %d\n",
  67                        acred->uid, acred->gid);
  68
  69        if (!(cred = kmalloc(sizeof(*cred), GFP_NOFS)))
  70                return ERR_PTR(-ENOMEM);
  71
  72        rpcauth_init_cred(&cred->uc_base, acred, auth, &unix_credops);
  73        cred->uc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
  74
  75        if (acred->group_info != NULL)
  76                groups = acred->group_info->ngroups;
  77        if (groups > NFS_NGROUPS)
  78                groups = NFS_NGROUPS;
  79
  80        cred->uc_gid = acred->gid;
  81        for (i = 0; i < groups; i++)
  82                cred->uc_gids[i] = GROUP_AT(acred->group_info, i);
  83        if (i < NFS_NGROUPS)
  84                cred->uc_gids[i] = NOGROUP;
  85
  86        return &cred->uc_base;
  87}
  88
  89static void
  90unx_free_cred(struct unx_cred *unx_cred)
  91{
  92        dprintk("RPC:       unx_free_cred %p\n", unx_cred);
  93        kfree(unx_cred);
  94}
  95
  96static void
  97unx_free_cred_callback(struct rcu_head *head)
  98{
  99        struct unx_cred *unx_cred = container_of(head, struct unx_cred, uc_base.cr_rcu);
 100        unx_free_cred(unx_cred);
 101}
 102
 103static void
 104unx_destroy_cred(struct rpc_cred *cred)
 105{
 106        call_rcu(&cred->cr_rcu, unx_free_cred_callback);
 107}
 108
 109/*
 110 * Match credentials against current process creds.
 111 * The root_override argument takes care of cases where the caller may
 112 * request root creds (e.g. for NFS swapping).
 113 */
 114static int
 115unx_match(struct auth_cred *acred, struct rpc_cred *rcred, int flags)
 116{
 117        struct unx_cred *cred = container_of(rcred, struct unx_cred, uc_base);
 118        unsigned int groups = 0;
 119        unsigned int i;
 120
 121
 122        if (cred->uc_uid != acred->uid || cred->uc_gid != acred->gid)
 123                return 0;
 124
 125        if (acred->group_info != NULL)
 126                groups = acred->group_info->ngroups;
 127        if (groups > NFS_NGROUPS)
 128                groups = NFS_NGROUPS;
 129        for (i = 0; i < groups ; i++)
 130                if (cred->uc_gids[i] != GROUP_AT(acred->group_info, i))
 131                        return 0;
 132        return 1;
 133}
 134
 135/*
 136 * Marshal credentials.
 137 * Maybe we should keep a cached credential for performance reasons.
 138 */
 139static __be32 *
 140unx_marshal(struct rpc_task *task, __be32 *p)
 141{
 142        struct rpc_clnt *clnt = task->tk_client;
 143        struct unx_cred *cred = container_of(task->tk_msg.rpc_cred, struct unx_cred, uc_base);
 144        __be32          *base, *hold;
 145        int             i;
 146
 147        *p++ = htonl(RPC_AUTH_UNIX);
 148        base = p++;
 149        *p++ = htonl(jiffies/HZ);
 150
 151        /*
 152         * Copy the UTS nodename captured when the client was created.
 153         */
 154        p = xdr_encode_array(p, clnt->cl_nodename, clnt->cl_nodelen);
 155
 156        *p++ = htonl((u32) cred->uc_uid);
 157        *p++ = htonl((u32) cred->uc_gid);
 158        hold = p++;
 159        for (i = 0; i < 16 && cred->uc_gids[i] != (gid_t) NOGROUP; i++)
 160                *p++ = htonl((u32) cred->uc_gids[i]);
 161        *hold = htonl(p - hold - 1);            /* gid array length */
 162        *base = htonl((p - base - 1) << 2);     /* cred length */
 163
 164        *p++ = htonl(RPC_AUTH_NULL);
 165        *p++ = htonl(0);
 166
 167        return p;
 168}
 169
 170/*
 171 * Refresh credentials. This is a no-op for AUTH_UNIX
 172 */
 173static int
 174unx_refresh(struct rpc_task *task)
 175{
 176        set_bit(RPCAUTH_CRED_UPTODATE, &task->tk_msg.rpc_cred->cr_flags);
 177        return 0;
 178}
 179
 180static __be32 *
 181unx_validate(struct rpc_task *task, __be32 *p)
 182{
 183        rpc_authflavor_t        flavor;
 184        u32                     size;
 185
 186        flavor = ntohl(*p++);
 187        if (flavor != RPC_AUTH_NULL &&
 188            flavor != RPC_AUTH_UNIX &&
 189            flavor != RPC_AUTH_SHORT) {
 190                printk("RPC: bad verf flavor: %u\n", flavor);
 191                return NULL;
 192        }
 193
 194        size = ntohl(*p++);
 195        if (size > RPC_MAX_AUTH_SIZE) {
 196                printk("RPC: giant verf size: %u\n", size);
 197                return NULL;
 198        }
 199        task->tk_msg.rpc_cred->cr_auth->au_rslack = (size >> 2) + 2;
 200        p += (size >> 2);
 201
 202        return p;
 203}
 204
 205void __init rpc_init_authunix(void)
 206{
 207        spin_lock_init(&unix_cred_cache.lock);
 208}
 209
 210const struct rpc_authops authunix_ops = {
 211        .owner          = THIS_MODULE,
 212        .au_flavor      = RPC_AUTH_UNIX,
 213        .au_name        = "UNIX",
 214        .create         = unx_create,
 215        .destroy        = unx_destroy,
 216        .lookup_cred    = unx_lookup_cred,
 217        .crcreate       = unx_create_cred,
 218};
 219
 220static
 221struct rpc_cred_cache   unix_cred_cache = {
 222};
 223
 224static
 225struct rpc_auth         unix_auth = {
 226        .au_cslack      = UNX_WRITESLACK,
 227        .au_rslack      = 2,                    /* assume AUTH_NULL verf */
 228        .au_ops         = &authunix_ops,
 229        .au_flavor      = RPC_AUTH_UNIX,
 230        .au_count       = ATOMIC_INIT(0),
 231        .au_credcache   = &unix_cred_cache,
 232};
 233
 234static
 235const struct rpc_credops unix_credops = {
 236        .cr_name        = "AUTH_UNIX",
 237        .crdestroy      = unx_destroy_cred,
 238        .crbind         = rpcauth_generic_bind_cred,
 239        .crmatch        = unx_match,
 240        .crmarshal      = unx_marshal,
 241        .crrefresh      = unx_refresh,
 242        .crvalidate     = unx_validate,
 243};
 244