Pileus Git - ~andy/linux/blob - net/sunrpc/auth_unix.c

   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
  17 struct 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_CRED_EXPIRE         (60 * HZ)
  25
  26 #define UNX_WRITESLACK          (21 + (UNX_MAXNODENAME >> 2))
  27
  28 #ifdef RPC_DEBUG
  29 # define RPCDBG_FACILITY        RPCDBG_AUTH
  30 #endif
  31
  32 static struct rpc_auth          unix_auth;
  33 static struct rpc_cred_cache    unix_cred_cache;
  34 static const struct rpc_credops unix_credops;
  35
  36 static struct rpc_auth *
  37 unx_create(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
  38 {
  39         dprintk("RPC:       creating UNIX authenticator for client %p\n",
  40                         clnt);
  41         if (atomic_inc_return(&unix_auth.au_count) == 1)
  42                 unix_cred_cache.nextgc = jiffies + (unix_cred_cache.expire >> 1);
  43         return &unix_auth;
  44 }
  45
  46 static void
  47 unx_destroy(struct rpc_auth *auth)
  48 {
  49         dprintk("RPC:       destroying UNIX authenticator %p\n", auth);
  50         rpcauth_clear_credcache(auth->au_credcache);
  51 }
  52
  53 /*
  54  * Lookup AUTH_UNIX creds for current process
  55  */
  56 static struct rpc_cred *
  57 unx_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  58 {
  59         return rpcauth_lookup_credcache(auth, acred, flags);
  60 }
  61
  62 static struct rpc_cred *
  63 unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  64 {
  65         struct unx_cred *cred;
  66         int             i;
  67
  68         dprintk("RPC:       allocating UNIX cred for uid %d gid %d\n",
  69                         acred->uid, acred->gid);
  70
  71         if (!(cred = kmalloc(sizeof(*cred), GFP_KERNEL)))
  72                 return ERR_PTR(-ENOMEM);
  73
  74         rpcauth_init_cred(&cred->uc_base, acred, auth, &unix_credops);
  75         cred->uc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
  76         if (flags & RPCAUTH_LOOKUP_ROOTCREDS) {
  77                 cred->uc_uid = 0;
  78                 cred->uc_gid = 0;
  79                 cred->uc_gids[0] = NOGROUP;
  80         } else {
  81                 int groups = acred->group_info->ngroups;
  82                 if (groups > NFS_NGROUPS)
  83                         groups = NFS_NGROUPS;
  84
  85                 cred->uc_gid = acred->gid;
  86                 for (i = 0; i < groups; i++)
  87                         cred->uc_gids[i] = GROUP_AT(acred->group_info, i);
  88                 if (i < NFS_NGROUPS)
  89                   cred->uc_gids[i] = NOGROUP;
  90         }
  91
  92         return &cred->uc_base;
  93 }
  94
  95 static void
  96 unx_free_cred(struct unx_cred *unx_cred)
  97 {
  98         dprintk("RPC:       unx_free_cred %p\n", unx_cred);
  99         kfree(unx_cred);
 100 }
 101
 102 static void
 103 unx_free_cred_callback(struct rcu_head *head)
 104 {
 105         struct unx_cred *unx_cred = container_of(head, struct unx_cred, uc_base.cr_rcu);
 106         unx_free_cred(unx_cred);
 107 }
 108
 109 static void
 110 unx_destroy_cred(struct rpc_cred *cred)
 111 {
 112         call_rcu(&cred->cr_rcu, unx_free_cred_callback);
 113 }
 114
 115 /*
 116  * Match credentials against current process creds.
 117  * The root_override argument takes care of cases where the caller may
 118  * request root creds (e.g. for NFS swapping).
 119  */
 120 static int
 121 unx_match(struct auth_cred *acred, struct rpc_cred *rcred, int flags)
 122 {
 123         struct unx_cred *cred = container_of(rcred, struct unx_cred, uc_base);
 124         int             i;
 125
 126         if (!(flags & RPCAUTH_LOOKUP_ROOTCREDS)) {
 127                 int groups;
 128
 129                 if (cred->uc_uid != acred->uid
 130                  || cred->uc_gid != acred->gid)
 131                         return 0;
 132
 133                 groups = acred->group_info->ngroups;
 134                 if (groups > NFS_NGROUPS)
 135                         groups = NFS_NGROUPS;
 136                 for (i = 0; i < groups ; i++)
 137                         if (cred->uc_gids[i] != GROUP_AT(acred->group_info, i))
 138                                 return 0;
 139                 return 1;
 140         }
 141         return (cred->uc_uid == 0
 142              && cred->uc_gid == 0
 143              && cred->uc_gids[0] == (gid_t) NOGROUP);
 144 }
 145
 146 /*
 147  * Marshal credentials.
 148  * Maybe we should keep a cached credential for performance reasons.
 149  */
 150 static __be32 *
 151 unx_marshal(struct rpc_task *task, __be32 *p)
 152 {
 153         struct rpc_clnt *clnt = task->tk_client;
 154         struct unx_cred *cred = container_of(task->tk_msg.rpc_cred, struct unx_cred, uc_base);
 155         __be32          *base, *hold;
 156         int             i;
 157
 158         *p++ = htonl(RPC_AUTH_UNIX);
 159         base = p++;
 160         *p++ = htonl(jiffies/HZ);
 161
 162         /*
 163          * Copy the UTS nodename captured when the client was created.
 164          */
 165         p = xdr_encode_array(p, clnt->cl_nodename, clnt->cl_nodelen);
 166
 167         *p++ = htonl((u32) cred->uc_uid);
 168         *p++ = htonl((u32) cred->uc_gid);
 169         hold = p++;
 170         for (i = 0; i < 16 && cred->uc_gids[i] != (gid_t) NOGROUP; i++)
 171                 *p++ = htonl((u32) cred->uc_gids[i]);
 172         *hold = htonl(p - hold - 1);            /* gid array length */
 173         *base = htonl((p - base - 1) << 2);     /* cred length */
 174
 175         *p++ = htonl(RPC_AUTH_NULL);
 176         *p++ = htonl(0);
 177
 178         return p;
 179 }
 180
 181 /*
 182  * Refresh credentials. This is a no-op for AUTH_UNIX
 183  */
 184 static int
 185 unx_refresh(struct rpc_task *task)
 186 {
 187         set_bit(RPCAUTH_CRED_UPTODATE, &task->tk_msg.rpc_cred->cr_flags);
 188         return 0;
 189 }
 190
 191 static __be32 *
 192 unx_validate(struct rpc_task *task, __be32 *p)
 193 {
 194         rpc_authflavor_t        flavor;
 195         u32                     size;
 196
 197         flavor = ntohl(*p++);
 198         if (flavor != RPC_AUTH_NULL &&
 199             flavor != RPC_AUTH_UNIX &&
 200             flavor != RPC_AUTH_SHORT) {
 201                 printk("RPC: bad verf flavor: %u\n", flavor);
 202                 return NULL;
 203         }
 204
 205         size = ntohl(*p++);
 206         if (size > RPC_MAX_AUTH_SIZE) {
 207                 printk("RPC: giant verf size: %u\n", size);
 208                 return NULL;
 209         }
 210         task->tk_auth->au_rslack = (size >> 2) + 2;
 211         p += (size >> 2);
 212
 213         return p;
 214 }
 215
 216 const struct rpc_authops authunix_ops = {
 217         .owner          = THIS_MODULE,
 218         .au_flavor      = RPC_AUTH_UNIX,
 219 #ifdef RPC_DEBUG
 220         .au_name        = "UNIX",
 221 #endif
 222         .create         = unx_create,
 223         .destroy        = unx_destroy,
 224         .lookup_cred    = unx_lookup_cred,
 225         .crcreate       = unx_create_cred,
 226 };
 227
 228 static
 229 struct rpc_cred_cache   unix_cred_cache = {
 230         .expire         = UNX_CRED_EXPIRE,
 231 };
 232
 233 static
 234 struct rpc_auth         unix_auth = {
 235         .au_cslack      = UNX_WRITESLACK,
 236         .au_rslack      = 2,                    /* assume AUTH_NULL verf */
 237         .au_ops         = &authunix_ops,
 238         .au_flavor      = RPC_AUTH_UNIX,
 239         .au_count       = ATOMIC_INIT(0),
 240         .au_credcache   = &unix_cred_cache,
 241 };
 242
 243 static
 244 const struct rpc_credops unix_credops = {
 245         .cr_name        = "AUTH_UNIX",
 246         .crdestroy      = unx_destroy_cred,
 247         .crmatch        = unx_match,
 248         .crmarshal      = unx_marshal,
 249         .crrefresh      = unx_refresh,
 250         .crvalidate     = unx_validate,
 251 };