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