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/slab.h>
  10#include <linux/types.h>
  11#include <linux/sched.h>
  12#include <linux/module.h>
  13#include <linux/sunrpc/clnt.h>
  14#include <linux/sunrpc/auth.h>
  15
  16#define NFS_NGROUPS     16
  17
  18struct unx_cred {
  19        struct rpc_cred         uc_base;
  20        gid_t                   uc_gid;
  21        gid_t                   uc_gids[NFS_NGROUPS];
  22};
  23#define uc_uid                  uc_base.cr_uid
  24
  25#define UNX_WRITESLACK          (21 + (UNX_MAXNODENAME >> 2))
  26
  27#ifdef RPC_DEBUG
  28# define RPCDBG_FACILITY        RPCDBG_AUTH
  29#endif
  30
  31static struct rpc_auth          unix_auth;
  32static struct rpc_cred_cache    unix_cred_cache;
  33static const struct rpc_credops unix_credops;
  34
  35static struct rpc_auth *
  36unx_create(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
  37{
  38        dprintk("RPC:       creating UNIX authenticator for client %p\n",
  39                        clnt);
  40        atomic_inc(&unix_auth.au_count);
  41        return &unix_auth;
  42}
  43
  44static void
  45unx_destroy(struct rpc_auth *auth)
  46{
  47        dprintk("RPC:       destroying UNIX authenticator %p\n", auth);
  48        rpcauth_clear_credcache(auth->au_credcache);
  49}
  50
  51/*
  52 * Lookup AUTH_UNIX creds for current process
  53 */
  54static struct rpc_cred *
  55unx_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  56{
  57        return rpcauth_lookup_credcache(auth, acred, flags);
  58}
  59
  60static struct rpc_cred *
  61unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  62{
  63        struct unx_cred *cred;
  64        unsigned int groups = 0;
  65        unsigned int i;
  66
  67        dprintk("RPC:       allocating UNIX cred for uid %d gid %d\n",
  68                        acred->uid, acred->gid);
  69
  70        if (!(cred = kmalloc(sizeof(*cred), GFP_NOFS)))
  71                return ERR_PTR(-ENOMEM);
  72
  73        rpcauth_init_cred(&cred->uc_base, acred, auth, &unix_credops);
  74        cred->uc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
  75
  76        if (acred->group_info != NULL)
  77                groups = acred->group_info->ngroups;
  78        if (groups > NFS_NGROUPS)
  79                groups = NFS_NGROUPS;
  80
  81        cred->uc_gid = acred->gid;
  82        for (i = 0; i < groups; i++)
  83                cred->uc_gids[i] = GROUP_AT(acred->group_info, i);
  84        if (i < NFS_NGROUPS)
  85                cred->uc_gids[i] = NOGROUP;
  86
  87        return &cred->uc_base;
  88}
  89
  90static void
  91unx_free_cred(struct unx_cred *unx_cred)
  92{
  93        dprintk("RPC:       unx_free_cred %p\n", unx_cred);
  94        kfree(unx_cred);
  95}
  96
  97static void
  98unx_free_cred_callback(struct rcu_head *head)
  99{
 100        struct unx_cred *unx_cred = container_of(head, struct unx_cred, uc_base.cr_rcu);
 101        unx_free_cred(unx_cred);
 102}
 103
 104static void
 105unx_destroy_cred(struct rpc_cred *cred)
 106{
 107        call_rcu(&cred->cr_rcu, unx_free_cred_callback);
 108}
 109
 110/*
 111 * Match credentials against current process creds.
 112 * The root_override argument takes care of cases where the caller may
 113 * request root creds (e.g. for NFS swapping).
 114 */
 115static int
 116unx_match(struct auth_cred *acred, struct rpc_cred *rcred, int flags)
 117{
 118        struct unx_cred *cred = container_of(rcred, struct unx_cred, uc_base);
 119        unsigned int groups = 0;
 120        unsigned int i;
 121
 122
 123        if (cred->uc_uid != acred->uid || cred->uc_gid != acred->gid)
 124                return 0;
 125
 126        if (acred->group_info != NULL)
 127                groups = acred->group_info->ngroups;
 128        if (groups > NFS_NGROUPS)
 129                groups = NFS_NGROUPS;
 130        for (i = 0; i < groups ; i++)
 131                if (cred->uc_gids[i] != GROUP_AT(acred->group_info, i))
 132                        return 0;
 133        return 1;
 134}
 135
 136/*
 137 * Marshal credentials.
 138 * Maybe we should keep a cached credential for performance reasons.
 139 */
 140static __be32 *
 141unx_marshal(struct rpc_task *task, __be32 *p)
 142{
 143        struct rpc_clnt *clnt = task->tk_client;
 144        struct unx_cred *cred = container_of(task->tk_msg.rpc_cred, struct unx_cred, uc_base);
 145        __be32          *base, *hold;
 146        int             i;
 147
 148        *p++ = htonl(RPC_AUTH_UNIX);
 149        base = p++;
 150        *p++ = htonl(jiffies/HZ);
 151
 152        /*
 153         * Copy the UTS nodename captured when the client was created.
 154         */
 155        p = xdr_encode_array(p, clnt->cl_nodename, clnt->cl_nodelen);
 156
 157        *p++ = htonl((u32) cred->uc_uid);
 158        *p++ = htonl((u32) cred->uc_gid);
 159        hold = p++;
 160        for (i = 0; i < 16 && cred->uc_gids[i] != (gid_t) NOGROUP; i++)
 161                *p++ = htonl((u32) cred->uc_gids[i]);
 162        *hold = htonl(p - hold - 1);            /* gid array length */
 163        *base = htonl((p - base - 1) << 2);     /* cred length */
 164
 165        *p++ = htonl(RPC_AUTH_NULL);
 166        *p++ = htonl(0);
 167
 168        return p;
 169}
 170
 171/*
 172 * Refresh credentials. This is a no-op for AUTH_UNIX
 173 */
 174static int
 175unx_refresh(struct rpc_task *task)
 176{
 177        set_bit(RPCAUTH_CRED_UPTODATE, &task->tk_msg.rpc_cred->cr_flags);
 178        return 0;
 179}
 180
 181static __be32 *
 182unx_validate(struct rpc_task *task, __be32 *p)
 183{
 184        rpc_authflavor_t        flavor;
 185        u32                     size;
 186
 187        flavor = ntohl(*p++);
 188        if (flavor != RPC_AUTH_NULL &&
 189            flavor != RPC_AUTH_UNIX &&
 190            flavor != RPC_AUTH_SHORT) {
 191                printk("RPC: bad verf flavor: %u\n", flavor);
 192                return NULL;
 193        }
 194
 195        size = ntohl(*p++);
 196        if (size > RPC_MAX_AUTH_SIZE) {
 197                printk("RPC: giant verf size: %u\n", size);
 198                return NULL;
 199        }
 200        task->tk_msg.rpc_cred->cr_auth->au_rslack = (size >> 2) + 2;
 201        p += (size >> 2);
 202
 203        return p;
 204}
 205
 206void __init rpc_init_authunix(void)
 207{
 208        spin_lock_init(&unix_cred_cache.lock);
 209}
 210
 211const struct rpc_authops authunix_ops = {
 212        .owner          = THIS_MODULE,
 213        .au_flavor      = RPC_AUTH_UNIX,
 214        .au_name        = "UNIX",
 215        .create         = unx_create,
 216        .destroy        = unx_destroy,
 217        .lookup_cred    = unx_lookup_cred,
 218        .crcreate       = unx_create_cred,
 219};
 220
 221static
 222struct rpc_cred_cache   unix_cred_cache = {
 223};
 224
 225static
 226struct rpc_auth         unix_auth = {
 227        .au_cslack      = UNX_WRITESLACK,
 228        .au_rslack      = 2,                    /* assume AUTH_NULL verf */
 229        .au_ops         = &authunix_ops,
 230        .au_flavor      = RPC_AUTH_UNIX,
 231        .au_count       = ATOMIC_INIT(0),
 232        .au_credcache   = &unix_cred_cache,
 233};
 234
 235static
 236const struct rpc_credops unix_credops = {
 237        .cr_name        = "AUTH_UNIX",
 238        .crdestroy      = unx_destroy_cred,
 239        .crbind         = rpcauth_generic_bind_cred,
 240        .crmatch        = unx_match,
 241        .crmarshal      = unx_marshal,
 242        .crrefresh      = unx_refresh,
 243        .crvalidate     = unx_validate,
 244};
 245