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 #include <linux/vserver/xid.h>
  15
  16 #define NFS_NGROUPS     16
  17
  18 struct unx_cred {
  19         struct rpc_cred         uc_base;
  20         gid_t                   uc_gid;
  21         xid_t                   uc_xid;
  22         gid_t                   uc_gids[NFS_NGROUPS];
  23 };
  24 #define uc_uid                  uc_base.cr_uid
  25 #define uc_count                uc_base.cr_count
  26 #define uc_flags                uc_base.cr_flags
  27 #define uc_expire               uc_base.cr_expire
  28
  29 #define UNX_CRED_EXPIRE         (60 * HZ)
  30
  31 #define UNX_WRITESLACK          (21 + (UNX_MAXNODENAME >> 2))
  32
  33 #ifdef RPC_DEBUG
  34 # define RPCDBG_FACILITY        RPCDBG_AUTH
  35 #endif
  36
  37 static struct rpc_auth          unix_auth;
  38 static struct rpc_cred_cache    unix_cred_cache;
  39 static struct rpc_credops       unix_credops;
  40
  41 static struct rpc_auth *
  42 unx_create(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
  43 {
  44         dprintk("RPC: creating UNIX authenticator for client %p\n", clnt);
  45         if (atomic_inc_return(&unix_auth.au_count) == 0)
  46                 unix_cred_cache.nextgc = jiffies + (unix_cred_cache.expire >> 1);
  47         return &unix_auth;
  48 }
  49
  50 static void
  51 unx_destroy(struct rpc_auth *auth)
  52 {
  53         dprintk("RPC: destroying UNIX authenticator %p\n", auth);
  54         rpcauth_free_credcache(auth);
  55 }
  56
  57 /*
  58  * Lookup AUTH_UNIX creds for current process
  59  */
  60 static struct rpc_cred *
  61 unx_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  62 {
  63         return rpcauth_lookup_credcache(auth, acred, flags);
  64 }
  65
  66 static struct rpc_cred *
  67 unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  68 {
  69         struct unx_cred *cred;
  70         int             i;
  71
  72         dprintk("RPC:      allocating UNIX cred for uid %d gid %d\n",
  73                                 acred->uid, acred->gid);
  74
  75         if (!(cred = kmalloc(sizeof(*cred), GFP_KERNEL)))
  76                 return ERR_PTR(-ENOMEM);
  77
  78         atomic_set(&cred->uc_count, 1);
  79         cred->uc_flags = RPCAUTH_CRED_UPTODATE;
  80         if (flags & RPCAUTH_LOOKUP_ROOTCREDS) {
  81                 cred->uc_uid = 0;
  82                 cred->uc_gid = 0;
  83                 cred->uc_xid = vx_current_xid();
  84                 cred->uc_gids[0] = NOGROUP;
  85         } else {
  86                 int groups = acred->group_info->ngroups;
  87                 if (groups > NFS_NGROUPS)
  88                         groups = NFS_NGROUPS;
  89
  90                 cred->uc_uid = acred->uid;
  91                 cred->uc_gid = acred->gid;
  92                 cred->uc_xid = acred->xid;
  93                 for (i = 0; i < groups; i++)
  94                         cred->uc_gids[i] = GROUP_AT(acred->group_info, i);
  95                 if (i < NFS_NGROUPS)
  96                   cred->uc_gids[i] = NOGROUP;
  97         }
  98         cred->uc_base.cr_ops = &unix_credops;
  99
 100         return (struct rpc_cred *) cred;
 101 }
 102
 103 static void
 104 unx_destroy_cred(struct rpc_cred *cred)
 105 {
 106         kfree(cred);
 107 }
 108
 109 /*
 110  * Match credentials against current process creds.
 111  * The root_override argument takes care of cases where the caller may
 112  * request root creds (e.g. for NFS swapping).
 113  */
 114 static int
 115 unx_match(struct auth_cred *acred, struct rpc_cred *rcred, int flags)
 116 {
 117         struct unx_cred *cred = (struct unx_cred *) rcred;
 118         int             i;
 119
 120         if (!(flags & RPCAUTH_LOOKUP_ROOTCREDS)) {
 121                 int groups;
 122
 123                 if (cred->uc_uid != acred->uid
 124                  || cred->uc_gid != acred->gid
 125                  || cred->uc_xid != acred->xid)
 126                         return 0;
 127
 128                 groups = acred->group_info->ngroups;
 129                 if (groups > NFS_NGROUPS)
 130                         groups = NFS_NGROUPS;
 131                 for (i = 0; i < groups ; i++)
 132                         if (cred->uc_gids[i] != GROUP_AT(acred->group_info, i))
 133                                 return 0;
 134                 return 1;
 135         }
 136         return (cred->uc_uid == 0
 137              && cred->uc_gid == 0
 138              && cred->uc_gids[0] == (gid_t) NOGROUP);
 139 }
 140
 141 /*
 142  * Marshal credentials.
 143  * Maybe we should keep a cached credential for performance reasons.
 144  */
 145 static u32 *
 146 unx_marshal(struct rpc_task *task, u32 *p)
 147 {
 148         struct rpc_clnt *clnt = task->tk_client;
 149         struct unx_cred *cred = (struct unx_cred *) task->tk_msg.rpc_cred;
 150         u32             *base, *hold;
 151         int             i, tagxid;
 152
 153         *p++ = htonl(RPC_AUTH_UNIX);
 154         base = p++;
 155         *p++ = htonl(jiffies/HZ);
 156
 157         /*
 158          * Copy the UTS nodename captured when the client was created.
 159          */
 160         p = xdr_encode_array(p, clnt->cl_nodename, clnt->cl_nodelen);
 161         tagxid = task->tk_client->cl_tagxid;
 162
 163         *p++ = htonl((u32) XIDINO_UID(tagxid,
 164                 cred->uc_uid, cred->uc_xid));
 165         *p++ = htonl((u32) XIDINO_GID(tagxid,
 166                 cred->uc_gid, cred->uc_xid));
 167         hold = p++;
 168         for (i = 0; i < 16 && cred->uc_gids[i] != (gid_t) NOGROUP; i++)
 169                 *p++ = htonl((u32) cred->uc_gids[i]);
 170         *hold = htonl(p - hold - 1);            /* gid array length */
 171         *base = htonl((p - base - 1) << 2);     /* cred length */
 172
 173         *p++ = htonl(RPC_AUTH_NULL);
 174         *p++ = htonl(0);
 175
 176         return p;
 177 }
 178
 179 /*
 180  * Refresh credentials. This is a no-op for AUTH_UNIX
 181  */
 182 static int
 183 unx_refresh(struct rpc_task *task)
 184 {
 185         task->tk_msg.rpc_cred->cr_flags |= RPCAUTH_CRED_UPTODATE;
 186         return 0;
 187 }
 188
 189 static u32 *
 190 unx_validate(struct rpc_task *task, u32 *p)
 191 {
 192         rpc_authflavor_t        flavor;
 193         u32                     size;
 194
 195         flavor = ntohl(*p++);
 196         if (flavor != RPC_AUTH_NULL &&
 197             flavor != RPC_AUTH_UNIX &&
 198             flavor != RPC_AUTH_SHORT) {
 199                 printk("RPC: bad verf flavor: %u\n", flavor);
 200                 return NULL;
 201         }
 202
 203         size = ntohl(*p++);
 204         if (size > RPC_MAX_AUTH_SIZE) {
 205                 printk("RPC: giant verf size: %u\n", size);
 206                 return NULL;
 207         }
 208         task->tk_auth->au_rslack = (size >> 2) + 2;
 209         p += (size >> 2);
 210
 211         return p;
 212 }
 213
 214 struct rpc_authops      authunix_ops = {
 215         .owner          = THIS_MODULE,
 216         .au_flavor      = RPC_AUTH_UNIX,
 217 #ifdef RPC_DEBUG
 218         .au_name        = "UNIX",
 219 #endif
 220         .create         = unx_create,
 221         .destroy        = unx_destroy,
 222         .lookup_cred    = unx_lookup_cred,
 223         .crcreate       = unx_create_cred,
 224 };
 225
 226 static
 227 struct rpc_cred_cache   unix_cred_cache = {
 228         .expire         = UNX_CRED_EXPIRE,
 229 };
 230
 231 static
 232 struct rpc_auth         unix_auth = {
 233         .au_cslack      = UNX_WRITESLACK,
 234         .au_rslack      = 2,                    /* assume AUTH_NULL verf */
 235         .au_ops         = &authunix_ops,
 236         .au_flavor      = RPC_AUTH_UNIX,
 237         .au_count       = ATOMIC_INIT(0),
 238         .au_credcache   = &unix_cred_cache,
 239 };
 240
 241 static
 242 struct rpc_credops      unix_credops = {
 243         .cr_name        = "AUTH_UNIX",
 244         .crdestroy      = unx_destroy_cred,
 245         .crmatch        = unx_match,
 246         .crmarshal      = unx_marshal,
 247         .crrefresh      = unx_refresh,
 248         .crvalidate     = unx_validate,
 249 };