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/socket.h>
  13 #include <linux/in.h>
  14 #include <linux/sunrpc/clnt.h>
  15 #include <linux/sunrpc/auth.h>
  16 #include <linux/vserver/xid.h>
  17
  18 #define NFS_NGROUPS     16
  19
  20 struct unx_cred {
  21         struct rpc_cred         uc_base;
  22         gid_t                   uc_gid;
  23         xid_t                   uc_xid;
  24         gid_t                   uc_gids[NFS_NGROUPS];
  25 };
  26 #define uc_uid                  uc_base.cr_uid
  27 #define uc_count                uc_base.cr_count
  28 #define uc_flags                uc_base.cr_flags
  29 #define uc_expire               uc_base.cr_expire
  30
  31 #define UNX_CRED_EXPIRE         (60 * HZ)
  32
  33 #define UNX_WRITESLACK          (21 + (UNX_MAXNODENAME >> 2))
  34
  35 #ifdef RPC_DEBUG
  36 # define RPCDBG_FACILITY        RPCDBG_AUTH
  37 #endif
  38
  39 static struct rpc_auth          unix_auth;
  40 static struct rpc_cred_cache    unix_cred_cache;
  41 static struct rpc_credops       unix_credops;
  42
  43 static struct rpc_auth *
  44 unx_create(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
  45 {
  46         dprintk("RPC: creating UNIX authenticator for client %p\n", clnt);
  47         if (atomic_inc_return(&unix_auth.au_count) == 0)
  48                 unix_cred_cache.nextgc = jiffies + (unix_cred_cache.expire >> 1);
  49         return &unix_auth;
  50 }
  51
  52 static void
  53 unx_destroy(struct rpc_auth *auth)
  54 {
  55         dprintk("RPC: destroying UNIX authenticator %p\n", auth);
  56         rpcauth_free_credcache(auth);
  57 }
  58
  59 /*
  60  * Lookup AUTH_UNIX creds for current process
  61  */
  62 static struct rpc_cred *
  63 unx_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  64 {
  65         return rpcauth_lookup_credcache(auth, acred, flags);
  66 }
  67
  68 static struct rpc_cred *
  69 unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  70 {
  71         struct unx_cred *cred;
  72         int             i;
  73
  74         dprintk("RPC:      allocating UNIX cred for uid %d gid %d\n",
  75                                 acred->uid, acred->gid);
  76
  77         if (!(cred = (struct unx_cred *) kmalloc(sizeof(*cred), GFP_KERNEL)))
  78                 return ERR_PTR(-ENOMEM);
  79
  80         atomic_set(&cred->uc_count, 1);
  81         cred->uc_flags = RPCAUTH_CRED_UPTODATE;
  82         if (flags & RPC_TASK_ROOTCREDS) {
  83                 cred->uc_uid = 0;
  84                 cred->uc_gid = 0;
  85                 cred->uc_xid = vx_current_xid();
  86                 cred->uc_gids[0] = NOGROUP;
  87         } else {
  88                 int groups = acred->group_info->ngroups;
  89                 if (groups > NFS_NGROUPS)
  90                         groups = NFS_NGROUPS;
  91
  92                 cred->uc_uid = acred->uid;
  93                 cred->uc_gid = acred->gid;
  94                 cred->uc_xid = acred->xid;
  95                 for (i = 0; i < groups; i++)
  96                         cred->uc_gids[i] = GROUP_AT(acred->group_info, i);
  97                 if (i < NFS_NGROUPS)
  98                   cred->uc_gids[i] = NOGROUP;
  99         }
 100         cred->uc_base.cr_ops = &unix_credops;
 101
 102         return (struct rpc_cred *) cred;
 103 }
 104
 105 static void
 106 unx_destroy_cred(struct rpc_cred *cred)
 107 {
 108         kfree(cred);
 109 }
 110
 111 /*
 112  * Match credentials against current process creds.
 113  * The root_override argument takes care of cases where the caller may
 114  * request root creds (e.g. for NFS swapping).
 115  */
 116 static int
 117 unx_match(struct auth_cred *acred, struct rpc_cred *rcred, int taskflags)
 118 {
 119         struct unx_cred *cred = (struct unx_cred *) rcred;
 120         int             i;
 121
 122         if (!(taskflags & RPC_TASK_ROOTCREDS)) {
 123                 int groups;
 124
 125                 if (cred->uc_uid != acred->uid
 126                  || cred->uc_gid != acred->gid
 127                  || cred->uc_xid != acred->xid)
 128                         return 0;
 129
 130                 groups = acred->group_info->ngroups;
 131                 if (groups > NFS_NGROUPS)
 132                         groups = NFS_NGROUPS;
 133                 for (i = 0; i < groups ; i++)
 134                         if (cred->uc_gids[i] != GROUP_AT(acred->group_info, i))
 135                                 return 0;
 136                 return 1;
 137         }
 138         return (cred->uc_uid == 0
 139              && cred->uc_gid == 0
 140              && cred->uc_gids[0] == (gid_t) NOGROUP);
 141 }
 142
 143 /*
 144  * Marshal credentials.
 145  * Maybe we should keep a cached credential for performance reasons.
 146  */
 147 static u32 *
 148 unx_marshal(struct rpc_task *task, u32 *p)
 149 {
 150         struct rpc_clnt *clnt = task->tk_client;
 151         struct unx_cred *cred = (struct unx_cred *) task->tk_msg.rpc_cred;
 152         u32             *base, *hold;
 153         int             i, tagxid;
 154
 155         *p++ = htonl(RPC_AUTH_UNIX);
 156         base = p++;
 157         *p++ = htonl(jiffies/HZ);
 158
 159         /*
 160          * Copy the UTS nodename captured when the client was created.
 161          */
 162         p = xdr_encode_array(p, clnt->cl_nodename, clnt->cl_nodelen);
 163         tagxid = task->tk_client->cl_tagxid;
 164
 165         *p++ = htonl((u32) XIDINO_UID(tagxid,
 166                 cred->uc_uid, cred->uc_xid));
 167         *p++ = htonl((u32) XIDINO_GID(tagxid,
 168                 cred->uc_gid, cred->uc_xid));
 169         hold = p++;
 170         for (i = 0; i < 16 && cred->uc_gids[i] != (gid_t) NOGROUP; i++)
 171                 *p++ = htonl((u32) cred->uc_gids[i]);
 172         *hold = htonl(p - hold - 1);            /* gid array length */
 173         *base = htonl((p - base - 1) << 2);     /* cred length */
 174
 175         *p++ = htonl(RPC_AUTH_NULL);
 176         *p++ = htonl(0);
 177
 178         return p;
 179 }
 180
 181 /*
 182  * Refresh credentials. This is a no-op for AUTH_UNIX
 183  */
 184 static int
 185 unx_refresh(struct rpc_task *task)
 186 {
 187         task->tk_msg.rpc_cred->cr_flags |= RPCAUTH_CRED_UPTODATE;
 188         return 0;
 189 }
 190
 191 static u32 *
 192 unx_validate(struct rpc_task *task, u32 *p)
 193 {
 194         rpc_authflavor_t        flavor;
 195         u32                     size;
 196
 197         flavor = ntohl(*p++);
 198         if (flavor != RPC_AUTH_NULL &&
 199             flavor != RPC_AUTH_UNIX &&
 200             flavor != RPC_AUTH_SHORT) {
 201                 printk("RPC: bad verf flavor: %u\n", flavor);
 202                 return NULL;
 203         }
 204
 205         size = ntohl(*p++);
 206         if (size > RPC_MAX_AUTH_SIZE) {
 207                 printk("RPC: giant verf size: %u\n", size);
 208                 return NULL;
 209         }
 210         task->tk_auth->au_rslack = (size >> 2) + 2;
 211         p += (size >> 2);
 212
 213         return p;
 214 }
 215
 216 struct rpc_authops      authunix_ops = {
 217         .owner          = THIS_MODULE,
 218         .au_flavor      = RPC_AUTH_UNIX,
 219 #ifdef RPC_DEBUG
 220         .au_name        = "UNIX",
 221 #endif
 222         .create         = unx_create,
 223         .destroy        = unx_destroy,
 224         .lookup_cred    = unx_lookup_cred,
 225         .crcreate       = unx_create_cred,
 226 };
 227
 228 static
 229 struct rpc_cred_cache   unix_cred_cache = {
 230         .expire         = UNX_CRED_EXPIRE,
 231 };
 232
 233 static
 234 struct rpc_auth         unix_auth = {
 235         .au_cslack      = UNX_WRITESLACK,
 236         .au_rslack      = 2,                    /* assume AUTH_NULL verf */
 237         .au_ops         = &authunix_ops,
 238         .au_count       = ATOMIC_INIT(0),
 239         .au_credcache   = &unix_cred_cache,
 240 };
 241
 242 static
 243 struct rpc_credops      unix_credops = {
 244         .cr_name        = "AUTH_UNIX",
 245         .crdestroy      = unx_destroy_cred,
 246         .crmatch        = unx_match,
 247         .crmarshal      = unx_marshal,
 248         .crrefresh      = unx_refresh,
 249         .crvalidate     = unx_validate,
 250 };