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/slab.h>
  10 #include <linux/types.h>
  11 #include <linux/sched.h>
  12 #include <linux/module.h>
  13 #include <linux/sunrpc/clnt.h>
  14 #include <linux/sunrpc/auth.h>
  15
  16 #define NFS_NGROUPS     16
  17
  18 struct unx_cred {
  19         struct rpc_cred         uc_base;
  20         gid_t                   uc_gid;
  21         gid_t                   uc_gids[NFS_NGROUPS];
  22 };
  23 #define uc_uid                  uc_base.cr_uid
  24
  25 #define UNX_WRITESLACK          (21 + (UNX_MAXNODENAME >> 2))
  26
  27 #ifdef RPC_DEBUG
  28 # define RPCDBG_FACILITY        RPCDBG_AUTH
  29 #endif
  30
  31 static struct rpc_auth          unix_auth;
  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_NOFS)))
  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         if (groups < NFS_NGROUPS &&
 133             cred->uc_gids[groups] != NOGROUP)
 134                 return 0;
 135         return 1;
 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 = container_of(task->tk_rqstp->rq_cred, struct unx_cred, uc_base);
 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         set_bit(RPCAUTH_CRED_UPTODATE, &task->tk_rqstp->rq_cred->cr_flags);
 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_rqstp->rq_cred->cr_auth->au_rslack = (size >> 2) + 2;
 203         p += (size >> 2);
 204
 205         return p;
 206 }
 207
 208 int __init rpc_init_authunix(void)
 209 {
 210         return rpcauth_init_credcache(&unix_auth);
 211 }
 212
 213 void rpc_destroy_authunix(void)
 214 {
 215         rpcauth_destroy_credcache(&unix_auth);
 216 }
 217
 218 const struct rpc_authops authunix_ops = {
 219         .owner          = THIS_MODULE,
 220         .au_flavor      = RPC_AUTH_UNIX,
 221         .au_name        = "UNIX",
 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_auth         unix_auth = {
 230         .au_cslack      = UNX_WRITESLACK,
 231         .au_rslack      = 2,                    /* assume AUTH_NULL verf */
 232         .au_ops         = &authunix_ops,
 233         .au_flavor      = RPC_AUTH_UNIX,
 234         .au_count       = ATOMIC_INIT(0),
 235 };
 236
 237 static
 238 const struct rpc_credops unix_credops = {
 239         .cr_name        = "AUTH_UNIX",
 240         .crdestroy      = unx_destroy_cred,
 241         .crbind         = rpcauth_generic_bind_cred,
 242         .crmatch        = unx_match,
 243         .crmarshal      = unx_marshal,
 244         .crrefresh      = unx_refresh,
 245         .crvalidate     = unx_validate,
 246 };