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         uid_t                   uc_puid;                /* process uid */
  25         gid_t                   uc_pgid;                /* process gid */
  26         xid_t                   uc_pxid;                /* process xid */
  27         gid_t                   uc_gids[NFS_NGROUPS];
  28 };
  29 #define uc_uid                  uc_base.cr_uid
  30 #define uc_count                uc_base.cr_count
  31 #define uc_flags                uc_base.cr_flags
  32 #define uc_expire               uc_base.cr_expire
  33
  34 #define UNX_CRED_EXPIRE         (60 * HZ)
  35
  36 #define UNX_WRITESLACK          (21 + (UNX_MAXNODENAME >> 2))
  37
  38 #ifdef RPC_DEBUG
  39 # define RPCDBG_FACILITY        RPCDBG_AUTH
  40 #endif
  41
  42 static struct rpc_credops       unix_credops;
  43
  44 static struct rpc_auth *
  45 unx_create(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
  46 {
  47         struct rpc_auth *auth;
  48
  49         dprintk("RPC: creating UNIX authenticator for client %p\n", clnt);
  50         if (!(auth = (struct rpc_auth *) kmalloc(sizeof(*auth), GFP_KERNEL)))
  51                 return NULL;
  52         auth->au_cslack = UNX_WRITESLACK;
  53         auth->au_rslack = 2;    /* assume AUTH_NULL verf */
  54         auth->au_expire = UNX_CRED_EXPIRE;
  55         auth->au_ops = &authunix_ops;
  56
  57         rpcauth_init_credcache(auth);
  58
  59         return auth;
  60 }
  61
  62 static void
  63 unx_destroy(struct rpc_auth *auth)
  64 {
  65         dprintk("RPC: destroying UNIX authenticator %p\n", auth);
  66         rpcauth_free_credcache(auth);
  67 }
  68
  69 static struct rpc_cred *
  70 unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  71 {
  72         struct unx_cred *cred;
  73         int             i;
  74
  75         dprintk("RPC:      allocating UNIX cred for uid %d gid %d\n",
  76                                 acred->uid, acred->gid);
  77
  78         if (!(cred = (struct unx_cred *) kmalloc(sizeof(*cred), GFP_KERNEL)))
  79                 return NULL;
  80
  81         atomic_set(&cred->uc_count, 0);
  82         cred->uc_flags = RPCAUTH_CRED_UPTODATE;
  83         if (flags & RPC_TASK_ROOTCREDS) {
  84                 cred->uc_uid = cred->uc_puid = 0;
  85                 cred->uc_gid = cred->uc_pgid = 0;
  86                 cred->uc_xid = cred->uc_pxid = current->xid;
  87                 cred->uc_gids[0] = NOGROUP;
  88         } else {
  89                 int groups = acred->group_info->ngroups;
  90                 if (groups > NFS_NGROUPS)
  91                         groups = NFS_NGROUPS;
  92
  93                 cred->uc_uid = acred->uid;
  94                 cred->uc_gid = acred->gid;
  95                 cred->uc_xid = acred->xid;
  96                 cred->uc_puid = current->uid;
  97                 cred->uc_pgid = current->gid;
  98                 cred->uc_pxid = current->xid;
  99                 for (i = 0; i < groups; i++)
 100                         cred->uc_gids[i] = GROUP_AT(acred->group_info, i);
 101                 if (i < NFS_NGROUPS)
 102                   cred->uc_gids[i] = NOGROUP;
 103         }
 104         cred->uc_base.cr_ops = &unix_credops;
 105
 106         return (struct rpc_cred *) cred;
 107 }
 108
 109 static void
 110 unx_destroy_cred(struct rpc_cred *cred)
 111 {
 112         kfree(cred);
 113 }
 114
 115 /*
 116  * Match credentials against current process creds.
 117  * The root_override argument takes care of cases where the caller may
 118  * request root creds (e.g. for NFS swapping).
 119  */
 120 static int
 121 unx_match(struct auth_cred *acred, struct rpc_cred *rcred, int taskflags)
 122 {
 123         struct unx_cred *cred = (struct unx_cred *) rcred;
 124         int             i;
 125
 126         if (!(taskflags & RPC_TASK_ROOTCREDS)) {
 127                 int groups;
 128
 129                 if (cred->uc_uid != acred->uid
 130                  || cred->uc_gid != acred->gid
 131                  || cred->uc_xid != acred->xid
 132                  || cred->uc_puid != current->uid
 133                  || cred->uc_pgid != current->gid
 134                  || cred->uc_pxid != current->xid)
 135                         return 0;
 136
 137                 groups = acred->group_info->ngroups;
 138                 if (groups > NFS_NGROUPS)
 139                         groups = NFS_NGROUPS;
 140                 for (i = 0; i < groups ; i++)
 141                         if (cred->uc_gids[i] != GROUP_AT(acred->group_info, i))
 142                                 return 0;
 143                 return 1;
 144         }
 145         return (cred->uc_uid == 0 && cred->uc_puid == 0
 146              && cred->uc_gid == 0 && cred->uc_pgid == 0
 147              && cred->uc_gids[0] == (gid_t) NOGROUP);
 148 }
 149
 150 /*
 151  * Marshal credentials.
 152  * Maybe we should keep a cached credential for performance reasons.
 153  */
 154 static u32 *
 155 unx_marshal(struct rpc_task *task, u32 *p, int ruid)
 156 {
 157         struct rpc_clnt *clnt = task->tk_client;
 158         struct unx_cred *cred = (struct unx_cred *) task->tk_msg.rpc_cred;
 159         u32             *base, *hold;
 160         int             i, tagxid;
 161
 162         *p++ = htonl(RPC_AUTH_UNIX);
 163         base = p++;
 164         *p++ = htonl(jiffies/HZ);
 165
 166         /*
 167          * Copy the UTS nodename captured when the client was created.
 168          */
 169         p = xdr_encode_array(p, clnt->cl_nodename, clnt->cl_nodelen);
 170         tagxid = task->tk_client->cl_tagxid;
 171
 172         /* Note: we don't use real uid if it involves raising privilege */
 173         if (ruid && cred->uc_puid != 0 && cred->uc_pgid != 0) {
 174                 *p++ = htonl((u32) XIDINO_UID(tagxid,
 175                         cred->uc_puid, cred->uc_pxid));
 176                 *p++ = htonl((u32) XIDINO_GID(tagxid,
 177                         cred->uc_pgid, cred->uc_pxid));
 178         } else {
 179                 *p++ = htonl((u32) XIDINO_UID(tagxid,
 180                         cred->uc_uid, cred->uc_xid));
 181                 *p++ = htonl((u32) XIDINO_GID(tagxid,
 182                         cred->uc_gid, cred->uc_xid));
 183         }
 184         hold = p++;
 185         for (i = 0; i < 16 && cred->uc_gids[i] != (gid_t) NOGROUP; i++)
 186                 *p++ = htonl((u32) cred->uc_gids[i]);
 187         *hold = htonl(p - hold - 1);            /* gid array length */
 188         *base = htonl((p - base - 1) << 2);     /* cred length */
 189
 190         *p++ = htonl(RPC_AUTH_NULL);
 191         *p++ = htonl(0);
 192
 193         return p;
 194 }
 195
 196 /*
 197  * Refresh credentials. This is a no-op for AUTH_UNIX
 198  */
 199 static int
 200 unx_refresh(struct rpc_task *task)
 201 {
 202         task->tk_msg.rpc_cred->cr_flags |= RPCAUTH_CRED_UPTODATE;
 203         return task->tk_status = -EACCES;
 204 }
 205
 206 static u32 *
 207 unx_validate(struct rpc_task *task, u32 *p)
 208 {
 209         rpc_authflavor_t        flavor;
 210         u32                     size;
 211
 212         flavor = ntohl(*p++);
 213         if (flavor != RPC_AUTH_NULL &&
 214             flavor != RPC_AUTH_UNIX &&
 215             flavor != RPC_AUTH_SHORT) {
 216                 printk("RPC: bad verf flavor: %u\n", flavor);
 217                 return NULL;
 218         }
 219
 220         size = ntohl(*p++);
 221         if (size > RPC_MAX_AUTH_SIZE) {
 222                 printk("RPC: giant verf size: %u\n", size);
 223                 return NULL;
 224         }
 225         task->tk_auth->au_rslack = (size >> 2) + 2;
 226         p += (size >> 2);
 227
 228         return p;
 229 }
 230
 231 struct rpc_authops      authunix_ops = {
 232         .owner          = THIS_MODULE,
 233         .au_flavor      = RPC_AUTH_UNIX,
 234 #ifdef RPC_DEBUG
 235         .au_name        = "UNIX",
 236 #endif
 237         .create         = unx_create,
 238         .destroy        = unx_destroy,
 239         .crcreate       = unx_create_cred,
 240 };
 241
 242 static
 243 struct rpc_credops      unix_credops = {
 244         .crdestroy      = unx_destroy_cred,
 245         .crmatch        = unx_match,
 246         .crmarshal      = unx_marshal,
 247         .crrefresh      = unx_refresh,
 248         .crvalidate     = unx_validate,
 249 };