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/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
  18 struct 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
  31 static struct rpc_auth          unix_auth;
  32 static struct rpc_cred_cache    unix_cred_cache;
  33 static const struct rpc_credops unix_credops;
  34
  35 static struct rpc_auth *
  36 unx_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
  44 static void
  45 unx_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  */
  54 static struct rpc_cred *
  55 unx_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  56 {
  57         return rpcauth_lookup_credcache(auth, acred, flags);
  58 }
  59
  60 static struct rpc_cred *
  61 unx_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
  90 static void
  91 unx_free_cred(struct unx_cred *unx_cred)
  92 {
  93         dprintk("RPC:       unx_free_cred %p\n", unx_cred);
  94         kfree(unx_cred);
  95 }
  96
  97 static void
  98 unx_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
 104 static void
 105 unx_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  */
 115 static int
 116 unx_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  */
 140 static __be32 *
 141 unx_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  */
 174 static int
 175 unx_refresh(struct rpc_task *task)
 176 {
 177         set_bit(RPCAUTH_CRED_UPTODATE, &task->tk_msg.rpc_cred->cr_flags);
 178         return 0;
 179 }
 180
 181 static __be32 *
 182 unx_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
 206 void __init rpc_init_authunix(void)
 207 {
 208         spin_lock_init(&unix_cred_cache.lock);
 209 }
 210
 211 const 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
 221 static
 222 struct rpc_cred_cache   unix_cred_cache = {
 223 };
 224
 225 static
 226 struct 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
 235 static
 236 const 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 };