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