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
  24 #define UNX_WRITESLACK          (21 + (UNX_MAXNODENAME >> 2))
  25
  26 #ifdef RPC_DEBUG
  27 # define RPCDBG_FACILITY        RPCDBG_AUTH
  28 #endif
  29
  30 static struct rpc_auth          unix_auth;
  31 static struct rpc_cred_cache    unix_cred_cache;
  32 static const struct rpc_credops unix_credops;
  33
  34 static struct rpc_auth *
  35 unx_create(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
  36 {
  37         dprintk("RPC:       creating UNIX authenticator for client %p\n",
  38                         clnt);
  39         atomic_inc(&unix_auth.au_count);
  40         return &unix_auth;
  41 }
  42
  43 static void
  44 unx_destroy(struct rpc_auth *auth)
  45 {
  46         dprintk("RPC:       destroying UNIX authenticator %p\n", auth);
  47         rpcauth_clear_credcache(auth->au_credcache);
  48 }
  49
  50 /*
  51  * Lookup AUTH_UNIX creds for current process
  52  */
  53 static struct rpc_cred *
  54 unx_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  55 {
  56         return rpcauth_lookup_credcache(auth, acred, flags);
  57 }
  58
  59 static struct rpc_cred *
  60 unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  61 {
  62         struct unx_cred *cred;
  63         unsigned int groups = 0;
  64         unsigned int i;
  65
  66         dprintk("RPC:       allocating UNIX cred for uid %d gid %d\n",
  67                         acred->uid, acred->gid);
  68
  69         if (!(cred = kmalloc(sizeof(*cred), GFP_KERNEL)))
  70                 return ERR_PTR(-ENOMEM);
  71
  72         rpcauth_init_cred(&cred->uc_base, acred, auth, &unix_credops);
  73         cred->uc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
  74
  75         if (acred->group_info != NULL)
  76                 groups = acred->group_info->ngroups;
  77         if (groups > NFS_NGROUPS)
  78                 groups = NFS_NGROUPS;
  79
  80         cred->uc_gid = acred->gid;
  81         for (i = 0; i < groups; i++)
  82                 cred->uc_gids[i] = GROUP_AT(acred->group_info, i);
  83         if (i < NFS_NGROUPS)
  84                 cred->uc_gids[i] = NOGROUP;
  85
  86         return &cred->uc_base;
  87 }
  88
  89 static void
  90 unx_free_cred(struct unx_cred *unx_cred)
  91 {
  92         dprintk("RPC:       unx_free_cred %p\n", unx_cred);
  93         kfree(unx_cred);
  94 }
  95
  96 static void
  97 unx_free_cred_callback(struct rcu_head *head)
  98 {
  99         struct unx_cred *unx_cred = container_of(head, struct unx_cred, uc_base.cr_rcu);
 100         unx_free_cred(unx_cred);
 101 }
 102
 103 static void
 104 unx_destroy_cred(struct rpc_cred *cred)
 105 {
 106         call_rcu(&cred->cr_rcu, unx_free_cred_callback);
 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 = container_of(rcred, struct unx_cred, uc_base);
 118         unsigned int groups = 0;
 119         unsigned int i;
 120
 121
 122         if (cred->uc_uid != acred->uid || cred->uc_gid != acred->gid)
 123                 return 0;
 124
 125         if (acred->group_info != NULL)
 126                 groups = acred->group_info->ngroups;
 127         if (groups > NFS_NGROUPS)
 128                 groups = NFS_NGROUPS;
 129         for (i = 0; i < groups ; i++)
 130                 if (cred->uc_gids[i] != GROUP_AT(acred->group_info, i))
 131                         return 0;
 132         return 1;
 133 }
 134
 135 /*
 136  * Marshal credentials.
 137  * Maybe we should keep a cached credential for performance reasons.
 138  */
 139 static __be32 *
 140 unx_marshal(struct rpc_task *task, __be32 *p)
 141 {
 142         struct rpc_clnt *clnt = task->tk_client;
 143         struct unx_cred *cred = container_of(task->tk_msg.rpc_cred, struct unx_cred, uc_base);
 144         __be32          *base, *hold;
 145         int             i;
 146
 147         *p++ = htonl(RPC_AUTH_UNIX);
 148         base = p++;
 149         *p++ = htonl(jiffies/HZ);
 150
 151         /*
 152          * Copy the UTS nodename captured when the client was created.
 153          */
 154         p = xdr_encode_array(p, clnt->cl_nodename, clnt->cl_nodelen);
 155
 156         *p++ = htonl((u32) cred->uc_uid);
 157         *p++ = htonl((u32) cred->uc_gid);
 158         hold = p++;
 159         for (i = 0; i < 16 && cred->uc_gids[i] != (gid_t) NOGROUP; i++)
 160                 *p++ = htonl((u32) cred->uc_gids[i]);
 161         *hold = htonl(p - hold - 1);            /* gid array length */
 162         *base = htonl((p - base - 1) << 2);     /* cred length */
 163
 164         *p++ = htonl(RPC_AUTH_NULL);
 165         *p++ = htonl(0);
 166
 167         return p;
 168 }
 169
 170 /*
 171  * Refresh credentials. This is a no-op for AUTH_UNIX
 172  */
 173 static int
 174 unx_refresh(struct rpc_task *task)
 175 {
 176         set_bit(RPCAUTH_CRED_UPTODATE, &task->tk_msg.rpc_cred->cr_flags);
 177         return 0;
 178 }
 179
 180 static __be32 *
 181 unx_validate(struct rpc_task *task, __be32 *p)
 182 {
 183         rpc_authflavor_t        flavor;
 184         u32                     size;
 185
 186         flavor = ntohl(*p++);
 187         if (flavor != RPC_AUTH_NULL &&
 188             flavor != RPC_AUTH_UNIX &&
 189             flavor != RPC_AUTH_SHORT) {
 190                 printk("RPC: bad verf flavor: %u\n", flavor);
 191                 return NULL;
 192         }
 193
 194         size = ntohl(*p++);
 195         if (size > RPC_MAX_AUTH_SIZE) {
 196                 printk("RPC: giant verf size: %u\n", size);
 197                 return NULL;
 198         }
 199         task->tk_msg.rpc_cred->cr_auth->au_rslack = (size >> 2) + 2;
 200         p += (size >> 2);
 201
 202         return p;
 203 }
 204
 205 void __init rpc_init_authunix(void)
 206 {
 207         spin_lock_init(&unix_cred_cache.lock);
 208 }
 209
 210 const struct rpc_authops authunix_ops = {
 211         .owner          = THIS_MODULE,
 212         .au_flavor      = RPC_AUTH_UNIX,
 213         .au_name        = "UNIX",
 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 };
 223
 224 static
 225 struct rpc_auth         unix_auth = {
 226         .au_cslack      = UNX_WRITESLACK,
 227         .au_rslack      = 2,                    /* assume AUTH_NULL verf */
 228         .au_ops         = &authunix_ops,
 229         .au_flavor      = RPC_AUTH_UNIX,
 230         .au_count       = ATOMIC_INIT(0),
 231         .au_credcache   = &unix_cred_cache,
 232 };
 233
 234 static
 235 const struct rpc_credops unix_credops = {
 236         .cr_name        = "AUTH_UNIX",
 237         .crdestroy      = unx_destroy_cred,
 238         .crbind         = rpcauth_generic_bind_cred,
 239         .crmatch        = unx_match,
 240         .crmarshal      = unx_marshal,
 241         .crrefresh      = unx_refresh,
 242         .crvalidate     = unx_validate,
 243 };