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         uid_t                   uc_puid;                /* process uid */
  24         gid_t                   uc_pgid;                /* process gid */
  25         gid_t                   uc_gids[NFS_NGROUPS];
  26 };
  27 #define uc_uid                  uc_base.cr_uid
  28 #define uc_count                uc_base.cr_count
  29 #define uc_flags                uc_base.cr_flags
  30 #define uc_expire               uc_base.cr_expire
  31
  32 #define UNX_CRED_EXPIRE         (60 * HZ)
  33
  34 #define UNX_WRITESLACK          (21 + (UNX_MAXNODENAME >> 2))
  35
  36 #ifdef RPC_DEBUG
  37 # define RPCDBG_FACILITY        RPCDBG_AUTH
  38 #endif
  39
  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         struct rpc_auth *auth;
  46
  47         dprintk("RPC: creating UNIX authenticator for client %p\n", clnt);
  48         if (!(auth = (struct rpc_auth *) kmalloc(sizeof(*auth), GFP_KERNEL)))
  49                 return NULL;
  50         auth->au_cslack = UNX_WRITESLACK;
  51         auth->au_rslack = 2;    /* assume AUTH_NULL verf */
  52         auth->au_expire = UNX_CRED_EXPIRE;
  53         auth->au_ops = &authunix_ops;
  54
  55         rpcauth_init_credcache(auth);
  56
  57         return auth;
  58 }
  59
  60 static void
  61 unx_destroy(struct rpc_auth *auth)
  62 {
  63         dprintk("RPC: destroying UNIX authenticator %p\n", auth);
  64         rpcauth_free_credcache(auth);
  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 = (struct unx_cred *) kmalloc(sizeof(*cred), GFP_KERNEL)))
  77                 return NULL;
  78
  79         atomic_set(&cred->uc_count, 0);
  80         cred->uc_flags = RPCAUTH_CRED_UPTODATE;
  81         if (flags & RPC_TASK_ROOTCREDS) {
  82                 cred->uc_uid = cred->uc_puid = 0;
  83                 cred->uc_gid = cred->uc_pgid = 0;
  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_puid = XIDINO_UID(current->uid, current->xid);
  93 //              cred->uc_pgid = XIDINO_GID(current->gid, current->xid);
  94                 cred->uc_puid = current->uid;
  95                 cred->uc_pgid = current->gid;
  96                 for (i = 0; i < groups; i++)
  97                         cred->uc_gids[i] = GROUP_AT(acred->group_info, i);
  98                 if (i < NFS_NGROUPS)
  99                   cred->uc_gids[i] = NOGROUP;
 100         }
 101         cred->uc_base.cr_ops = &unix_credops;
 102
 103         return (struct rpc_cred *) cred;
 104 }
 105
 106 static void
 107 unx_destroy_cred(struct rpc_cred *cred)
 108 {
 109         kfree(cred);
 110 }
 111
 112 /*
 113  * Match credentials against current process creds.
 114  * The root_override argument takes care of cases where the caller may
 115  * request root creds (e.g. for NFS swapping).
 116  */
 117 static int
 118 unx_match(struct auth_cred *acred, struct rpc_cred *rcred, int taskflags)
 119 {
 120         struct unx_cred *cred = (struct unx_cred *) rcred;
 121         int             i;
 122
 123         if (!(taskflags & RPC_TASK_ROOTCREDS)) {
 124                 int groups;
 125
 126                 if (cred->uc_uid != acred->uid
 127                  || cred->uc_gid != acred->gid
 128                  || cred->uc_puid != XIDINO_UID(current->uid, current->xid)
 129                  || cred->uc_pgid != XIDINO_GID(current->gid, current->xid))
 130                         return 0;
 131
 132                 groups = acred->group_info->ngroups;
 133                 if (groups > NFS_NGROUPS)
 134                         groups = NFS_NGROUPS;
 135                 for (i = 0; i < groups ; i++)
 136                         if (cred->uc_gids[i] != GROUP_AT(acred->group_info, i))
 137                                 return 0;
 138                 return 1;
 139         }
 140         return (cred->uc_uid == 0 && cred->uc_puid == 0
 141              && cred->uc_gid == 0 && cred->uc_pgid == 0
 142              && cred->uc_gids[0] == (gid_t) NOGROUP);
 143 }
 144
 145 /*
 146  * Marshal credentials.
 147  * Maybe we should keep a cached credential for performance reasons.
 148  */
 149 static u32 *
 150 unx_marshal(struct rpc_task *task, u32 *p, int ruid)
 151 {
 152         struct rpc_clnt *clnt = task->tk_client;
 153         struct unx_cred *cred = (struct unx_cred *) task->tk_msg.rpc_cred;
 154         u32             *base, *hold;
 155         int             i;
 156
 157         *p++ = htonl(RPC_AUTH_UNIX);
 158         base = p++;
 159         *p++ = htonl(jiffies/HZ);
 160
 161         /*
 162          * Copy the UTS nodename captured when the client was created.
 163          */
 164         p = xdr_encode_array(p, clnt->cl_nodename, clnt->cl_nodelen);
 165
 166         /* Note: we don't use real uid if it involves raising privilege */
 167         if (ruid && cred->uc_puid != 0 && cred->uc_pgid != 0) {
 168                 *p++ = htonl((u32) cred->uc_puid);
 169                 *p++ = htonl((u32) cred->uc_pgid);
 170         } else {
 171                 *p++ = htonl((u32) cred->uc_uid);
 172                 *p++ = htonl((u32) cred->uc_gid);
 173         }
 174         hold = p++;
 175         for (i = 0; i < 16 && cred->uc_gids[i] != (gid_t) NOGROUP; i++)
 176                 *p++ = htonl((u32) cred->uc_gids[i]);
 177         *hold = htonl(p - hold - 1);            /* gid array length */
 178         *base = htonl((p - base - 1) << 2);     /* cred length */
 179
 180         *p++ = htonl(RPC_AUTH_NULL);
 181         *p++ = htonl(0);
 182
 183         return p;
 184 }
 185
 186 /*
 187  * Refresh credentials. This is a no-op for AUTH_UNIX
 188  */
 189 static int
 190 unx_refresh(struct rpc_task *task)
 191 {
 192         task->tk_msg.rpc_cred->cr_flags |= RPCAUTH_CRED_UPTODATE;
 193         return task->tk_status = -EACCES;
 194 }
 195
 196 static u32 *
 197 unx_validate(struct rpc_task *task, u32 *p)
 198 {
 199         rpc_authflavor_t        flavor;
 200         u32                     size;
 201
 202         flavor = ntohl(*p++);
 203         if (flavor != RPC_AUTH_NULL &&
 204             flavor != RPC_AUTH_UNIX &&
 205             flavor != RPC_AUTH_SHORT) {
 206                 printk("RPC: bad verf flavor: %u\n", flavor);
 207                 return NULL;
 208         }
 209
 210         size = ntohl(*p++);
 211         if (size > RPC_MAX_AUTH_SIZE) {
 212                 printk("RPC: giant verf size: %u\n", size);
 213                 return NULL;
 214         }
 215         task->tk_auth->au_rslack = (size >> 2) + 2;
 216         p += (size >> 2);
 217
 218         return p;
 219 }
 220
 221 struct rpc_authops      authunix_ops = {
 222         .owner          = THIS_MODULE,
 223         .au_flavor      = RPC_AUTH_UNIX,
 224 #ifdef RPC_DEBUG
 225         .au_name        = "UNIX",
 226 #endif
 227         .create         = unx_create,
 228         .destroy        = unx_destroy,
 229         .crcreate       = unx_create_cred,
 230 };
 231
 232 static
 233 struct rpc_credops      unix_credops = {
 234         .crdestroy      = unx_destroy_cred,
 235         .crmatch        = unx_match,
 236         .crmarshal      = unx_marshal,
 237         .crrefresh      = unx_refresh,
 238         .crvalidate     = unx_validate,
 239 };