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 #define uc_count                uc_base.cr_count
  24 #define uc_flags                uc_base.cr_flags
  25 #define uc_expire               uc_base.cr_expire
  26
  27 #define UNX_CRED_EXPIRE         (60 * HZ)
  28
  29 #define UNX_WRITESLACK          (21 + (UNX_MAXNODENAME >> 2))
  30
  31 #ifdef RPC_DEBUG
  32 # define RPCDBG_FACILITY        RPCDBG_AUTH
  33 #endif
  34
  35 static struct rpc_auth          unix_auth;
  36 static struct rpc_cred_cache    unix_cred_cache;
  37 static struct rpc_credops       unix_credops;
  38
  39 static struct rpc_auth *
  40 unx_create(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
  41 {
  42         dprintk("RPC: creating UNIX authenticator for client %p\n", clnt);
  43         if (atomic_inc_return(&unix_auth.au_count) == 0)
  44                 unix_cred_cache.nextgc = jiffies + (unix_cred_cache.expire >> 1);
  45         return &unix_auth;
  46 }
  47
  48 static void
  49 unx_destroy(struct rpc_auth *auth)
  50 {
  51         dprintk("RPC: destroying UNIX authenticator %p\n", auth);
  52         rpcauth_free_credcache(auth);
  53 }
  54
  55 /*
  56  * Lookup AUTH_UNIX creds for current process
  57  */
  58 static struct rpc_cred *
  59 unx_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  60 {
  61         return rpcauth_lookup_credcache(auth, acred, flags);
  62 }
  63
  64 static struct rpc_cred *
  65 unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  66 {
  67         struct unx_cred *cred;
  68         int             i;
  69
  70         dprintk("RPC:      allocating UNIX cred for uid %d gid %d\n",
  71                                 acred->uid, acred->gid);
  72
  73         if (!(cred = (struct unx_cred *) kmalloc(sizeof(*cred), GFP_KERNEL)))
  74                 return ERR_PTR(-ENOMEM);
  75
  76         atomic_set(&cred->uc_count, 1);
  77         cred->uc_flags = RPCAUTH_CRED_UPTODATE;
  78         if (flags & RPC_TASK_ROOTCREDS) {
  79                 cred->uc_uid = 0;
  80                 cred->uc_gid = 0;
  81                 cred->uc_gids[0] = NOGROUP;
  82         } else {
  83                 int groups = acred->group_info->ngroups;
  84                 if (groups > NFS_NGROUPS)
  85                         groups = NFS_NGROUPS;
  86
  87                 cred->uc_uid = acred->uid;
  88                 cred->uc_gid = acred->gid;
  89                 for (i = 0; i < groups; i++)
  90                         cred->uc_gids[i] = GROUP_AT(acred->group_info, i);
  91                 if (i < NFS_NGROUPS)
  92                   cred->uc_gids[i] = NOGROUP;
  93         }
  94         cred->uc_base.cr_ops = &unix_credops;
  95
  96         return (struct rpc_cred *) cred;
  97 }
  98
  99 static void
 100 unx_destroy_cred(struct rpc_cred *cred)
 101 {
 102         kfree(cred);
 103 }
 104
 105 /*
 106  * Match credentials against current process creds.
 107  * The root_override argument takes care of cases where the caller may
 108  * request root creds (e.g. for NFS swapping).
 109  */
 110 static int
 111 unx_match(struct auth_cred *acred, struct rpc_cred *rcred, int taskflags)
 112 {
 113         struct unx_cred *cred = (struct unx_cred *) rcred;
 114         int             i;
 115
 116         if (!(taskflags & RPC_TASK_ROOTCREDS)) {
 117                 int groups;
 118
 119                 if (cred->uc_uid != acred->uid
 120                  || cred->uc_gid != acred->gid)
 121                         return 0;
 122
 123                 groups = acred->group_info->ngroups;
 124                 if (groups > NFS_NGROUPS)
 125                         groups = NFS_NGROUPS;
 126                 for (i = 0; i < groups ; i++)
 127                         if (cred->uc_gids[i] != GROUP_AT(acred->group_info, i))
 128                                 return 0;
 129                 return 1;
 130         }
 131         return (cred->uc_uid == 0
 132              && cred->uc_gid == 0
 133              && cred->uc_gids[0] == (gid_t) NOGROUP);
 134 }
 135
 136 /*
 137  * Marshal credentials.
 138  * Maybe we should keep a cached credential for performance reasons.
 139  */
 140 static u32 *
 141 unx_marshal(struct rpc_task *task, u32 *p)
 142 {
 143         struct rpc_clnt *clnt = task->tk_client;
 144         struct unx_cred *cred = (struct unx_cred *) task->tk_msg.rpc_cred;
 145         u32             *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  */
 174 static int
 175 unx_refresh(struct rpc_task *task)
 176 {
 177         task->tk_msg.rpc_cred->cr_flags |= RPCAUTH_CRED_UPTODATE;
 178         return 0;
 179 }
 180
 181 static u32 *
 182 unx_validate(struct rpc_task *task, u32 *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_auth->au_rslack = (size >> 2) + 2;
 201         p += (size >> 2);
 202
 203         return p;
 204 }
 205
 206 struct rpc_authops      authunix_ops = {
 207         .owner          = THIS_MODULE,
 208         .au_flavor      = RPC_AUTH_UNIX,
 209 #ifdef RPC_DEBUG
 210         .au_name        = "UNIX",
 211 #endif
 212         .create         = unx_create,
 213         .destroy        = unx_destroy,
 214         .lookup_cred    = unx_lookup_cred,
 215         .crcreate       = unx_create_cred,
 216 };
 217
 218 static
 219 struct rpc_cred_cache   unix_cred_cache = {
 220         .expire         = UNX_CRED_EXPIRE,
 221 };
 222
 223 static
 224 struct rpc_auth         unix_auth = {
 225         .au_cslack      = UNX_WRITESLACK,
 226         .au_rslack      = 2,                    /* assume AUTH_NULL verf */
 227         .au_ops         = &authunix_ops,
 228         .au_count       = ATOMIC_INIT(0),
 229         .au_credcache   = &unix_cred_cache,
 230 };
 231
 232 static
 233 struct rpc_credops      unix_credops = {
 234         .cr_name        = "AUTH_UNIX",
 235         .crdestroy      = unx_destroy_cred,
 236         .crmatch        = unx_match,
 237         .crmarshal      = unx_marshal,
 238         .crrefresh      = unx_refresh,
 239         .crvalidate     = unx_validate,
 240 };