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 = 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 (struct rpc_cred *) cred;
  93 }
  94
  95 static void
  96 unx_destroy_cred(struct rpc_cred *cred)
  97 {
  98         kfree(cred);
  99 }
 100
 101 /*
 102  * Match credentials against current process creds.
 103  * The root_override argument takes care of cases where the caller may
 104  * request root creds (e.g. for NFS swapping).
 105  */
 106 static int
 107 unx_match(struct auth_cred *acred, struct rpc_cred *rcred, int flags)
 108 {
 109         struct unx_cred *cred = (struct unx_cred *) rcred;
 110         int             i;
 111
 112         if (!(flags & RPCAUTH_LOOKUP_ROOTCREDS)) {
 113                 int groups;
 114
 115                 if (cred->uc_uid != acred->uid
 116                  || cred->uc_gid != acred->gid)
 117                         return 0;
 118
 119                 groups = acred->group_info->ngroups;
 120                 if (groups > NFS_NGROUPS)
 121                         groups = NFS_NGROUPS;
 122                 for (i = 0; i < groups ; i++)
 123                         if (cred->uc_gids[i] != GROUP_AT(acred->group_info, i))
 124                                 return 0;
 125                 return 1;
 126         }
 127         return (cred->uc_uid == 0
 128              && cred->uc_gid == 0
 129              && cred->uc_gids[0] == (gid_t) NOGROUP);
 130 }
 131
 132 /*
 133  * Marshal credentials.
 134  * Maybe we should keep a cached credential for performance reasons.
 135  */
 136 static __be32 *
 137 unx_marshal(struct rpc_task *task, __be32 *p)
 138 {
 139         struct rpc_clnt *clnt = task->tk_client;
 140         struct unx_cred *cred = (struct unx_cred *) task->tk_msg.rpc_cred;
 141         __be32          *base, *hold;
 142         int             i;
 143
 144         *p++ = htonl(RPC_AUTH_UNIX);
 145         base = p++;
 146         *p++ = htonl(jiffies/HZ);
 147
 148         /*
 149          * Copy the UTS nodename captured when the client was created.
 150          */
 151         p = xdr_encode_array(p, clnt->cl_nodename, clnt->cl_nodelen);
 152
 153         *p++ = htonl((u32) cred->uc_uid);
 154         *p++ = htonl((u32) cred->uc_gid);
 155         hold = p++;
 156         for (i = 0; i < 16 && cred->uc_gids[i] != (gid_t) NOGROUP; i++)
 157                 *p++ = htonl((u32) cred->uc_gids[i]);
 158         *hold = htonl(p - hold - 1);            /* gid array length */
 159         *base = htonl((p - base - 1) << 2);     /* cred length */
 160
 161         *p++ = htonl(RPC_AUTH_NULL);
 162         *p++ = htonl(0);
 163
 164         return p;
 165 }
 166
 167 /*
 168  * Refresh credentials. This is a no-op for AUTH_UNIX
 169  */
 170 static int
 171 unx_refresh(struct rpc_task *task)
 172 {
 173         task->tk_msg.rpc_cred->cr_flags |= RPCAUTH_CRED_UPTODATE;
 174         return 0;
 175 }
 176
 177 static __be32 *
 178 unx_validate(struct rpc_task *task, __be32 *p)
 179 {
 180         rpc_authflavor_t        flavor;
 181         u32                     size;
 182
 183         flavor = ntohl(*p++);
 184         if (flavor != RPC_AUTH_NULL &&
 185             flavor != RPC_AUTH_UNIX &&
 186             flavor != RPC_AUTH_SHORT) {
 187                 printk("RPC: bad verf flavor: %u\n", flavor);
 188                 return NULL;
 189         }
 190
 191         size = ntohl(*p++);
 192         if (size > RPC_MAX_AUTH_SIZE) {
 193                 printk("RPC: giant verf size: %u\n", size);
 194                 return NULL;
 195         }
 196         task->tk_auth->au_rslack = (size >> 2) + 2;
 197         p += (size >> 2);
 198
 199         return p;
 200 }
 201
 202 const struct rpc_authops authunix_ops = {
 203         .owner          = THIS_MODULE,
 204         .au_flavor      = RPC_AUTH_UNIX,
 205 #ifdef RPC_DEBUG
 206         .au_name        = "UNIX",
 207 #endif
 208         .create         = unx_create,
 209         .destroy        = unx_destroy,
 210         .lookup_cred    = unx_lookup_cred,
 211         .crcreate       = unx_create_cred,
 212 };
 213
 214 static
 215 struct rpc_cred_cache   unix_cred_cache = {
 216         .expire         = UNX_CRED_EXPIRE,
 217 };
 218
 219 static
 220 struct rpc_auth         unix_auth = {
 221         .au_cslack      = UNX_WRITESLACK,
 222         .au_rslack      = 2,                    /* assume AUTH_NULL verf */
 223         .au_ops         = &authunix_ops,
 224         .au_flavor      = RPC_AUTH_UNIX,
 225         .au_count       = ATOMIC_INIT(0),
 226         .au_credcache   = &unix_cred_cache,
 227 };
 228
 229 static
 230 const struct rpc_credops unix_credops = {
 231         .cr_name        = "AUTH_UNIX",
 232         .crdestroy      = unx_destroy_cred,
 233         .crmatch        = unx_match,
 234         .crmarshal      = unx_marshal,
 235         .crrefresh      = unx_refresh,
 236         .crvalidate     = unx_validate,
 237 };