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
  17 #define NFS_NGROUPS     16
  18
  19 struct unx_cred {
  20         struct rpc_cred         uc_base;
  21         gid_t                   uc_gid;
  22         uid_t                   uc_puid;                /* process uid */
  23         gid_t                   uc_pgid;                /* process gid */
  24         gid_t                   uc_gids[NFS_NGROUPS];
  25 };
  26 #define uc_uid                  uc_base.cr_uid
  27 #define uc_count                uc_base.cr_count
  28 #define uc_flags                uc_base.cr_flags
  29 #define uc_expire               uc_base.cr_expire
  30
  31 #define UNX_CRED_EXPIRE         (60 * HZ)
  32
  33 #define UNX_WRITESLACK          (21 + (UNX_MAXNODENAME >> 2))
  34
  35 #ifdef RPC_DEBUG
  36 # define RPCDBG_FACILITY        RPCDBG_AUTH
  37 #endif
  38
  39 static struct rpc_credops       unix_credops;
  40
  41 static struct rpc_auth *
  42 unx_create(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
  43 {
  44         struct rpc_auth *auth;
  45
  46         dprintk("RPC: creating UNIX authenticator for client %p\n", clnt);
  47         if (!(auth = (struct rpc_auth *) kmalloc(sizeof(*auth), GFP_KERNEL)))
  48                 return NULL;
  49         auth->au_cslack = UNX_WRITESLACK;
  50         auth->au_rslack = 2;    /* assume AUTH_NULL verf */
  51         auth->au_expire = UNX_CRED_EXPIRE;
  52         auth->au_ops = &authunix_ops;
  53
  54         rpcauth_init_credcache(auth);
  55
  56         return auth;
  57 }
  58
  59 static void
  60 unx_destroy(struct rpc_auth *auth)
  61 {
  62         dprintk("RPC: destroying UNIX authenticator %p\n", auth);
  63         rpcauth_free_credcache(auth);
  64 }
  65
  66 static struct rpc_cred *
  67 unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  68 {
  69         struct unx_cred *cred;
  70         int             i;
  71
  72         dprintk("RPC:      allocating UNIX cred for uid %d gid %d\n",
  73                                 acred->uid, acred->gid);
  74
  75         if (!(cred = (struct unx_cred *) kmalloc(sizeof(*cred), GFP_KERNEL)))
  76                 return NULL;
  77
  78         atomic_set(&cred->uc_count, 0);
  79         cred->uc_flags = RPCAUTH_CRED_UPTODATE;
  80         if (flags & RPC_TASK_ROOTCREDS) {
  81                 cred->uc_uid = cred->uc_puid = 0;
  82                 cred->uc_gid = cred->uc_pgid = 0;
  83                 cred->uc_gids[0] = NOGROUP;
  84         } else {
  85                 int groups = acred->group_info->ngroups;
  86                 if (groups > NFS_NGROUPS)
  87                         groups = NFS_NGROUPS;
  88
  89                 cred->uc_uid = acred->uid;
  90                 cred->uc_gid = acred->gid;
  91                 cred->uc_puid = current->uid;
  92                 cred->uc_pgid = current->gid;
  93                 for (i = 0; i < groups; i++)
  94                         cred->uc_gids[i] = GROUP_AT(acred->group_info, i);
  95                 if (i < NFS_NGROUPS)
  96                   cred->uc_gids[i] = NOGROUP;
  97         }
  98         cred->uc_base.cr_ops = &unix_credops;
  99
 100         return (struct rpc_cred *) cred;
 101 }
 102
 103 static void
 104 unx_destroy_cred(struct rpc_cred *cred)
 105 {
 106         kfree(cred);
 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 taskflags)
 116 {
 117         struct unx_cred *cred = (struct unx_cred *) rcred;
 118         int             i;
 119
 120         if (!(taskflags & RPC_TASK_ROOTCREDS)) {
 121                 int groups;
 122
 123                 if (cred->uc_uid != acred->uid
 124                  || cred->uc_gid != acred->gid
 125                  || cred->uc_puid != current->uid
 126                  || cred->uc_pgid != current->gid)
 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 && cred->uc_puid == 0
 138              && cred->uc_gid == 0 && cred->uc_pgid == 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, int ruid)
 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;
 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
 163         /* Note: we don't use real uid if it involves raising privilege */
 164         if (ruid && cred->uc_puid != 0 && cred->uc_pgid != 0) {
 165                 *p++ = htonl((u32) cred->uc_puid);
 166                 *p++ = htonl((u32) cred->uc_pgid);
 167         } else {
 168                 *p++ = htonl((u32) cred->uc_uid);
 169                 *p++ = htonl((u32) cred->uc_gid);
 170         }
 171         hold = p++;
 172         for (i = 0; i < 16 && cred->uc_gids[i] != (gid_t) NOGROUP; i++)
 173                 *p++ = htonl((u32) cred->uc_gids[i]);
 174         *hold = htonl(p - hold - 1);            /* gid array length */
 175         *base = htonl((p - base - 1) << 2);     /* cred length */
 176
 177         *p++ = htonl(RPC_AUTH_NULL);
 178         *p++ = htonl(0);
 179
 180         return p;
 181 }
 182
 183 /*
 184  * Refresh credentials. This is a no-op for AUTH_UNIX
 185  */
 186 static int
 187 unx_refresh(struct rpc_task *task)
 188 {
 189         task->tk_msg.rpc_cred->cr_flags |= RPCAUTH_CRED_UPTODATE;
 190         return task->tk_status = -EACCES;
 191 }
 192
 193 static u32 *
 194 unx_validate(struct rpc_task *task, u32 *p)
 195 {
 196         rpc_authflavor_t        flavor;
 197         u32                     size;
 198
 199         flavor = ntohl(*p++);
 200         if (flavor != RPC_AUTH_NULL &&
 201             flavor != RPC_AUTH_UNIX &&
 202             flavor != RPC_AUTH_SHORT) {
 203                 printk("RPC: bad verf flavor: %u\n", flavor);
 204                 return NULL;
 205         }
 206
 207         size = ntohl(*p++);
 208         if (size > RPC_MAX_AUTH_SIZE) {
 209                 printk("RPC: giant verf size: %u\n", size);
 210                 return NULL;
 211         }
 212         task->tk_auth->au_rslack = (size >> 2) + 2;
 213         p += (size >> 2);
 214
 215         return p;
 216 }
 217
 218 struct rpc_authops      authunix_ops = {
 219         .owner          = THIS_MODULE,
 220         .au_flavor      = RPC_AUTH_UNIX,
 221 #ifdef RPC_DEBUG
 222         .au_name        = "UNIX",
 223 #endif
 224         .create         = unx_create,
 225         .destroy        = unx_destroy,
 226         .crcreate       = unx_create_cred,
 227 };
 228
 229 static
 230 struct rpc_credops      unix_credops = {
 231         .crdestroy      = unx_destroy_cred,
 232         .crmatch        = unx_match,
 233         .crmarshal      = unx_marshal,
 234         .crrefresh      = unx_refresh,
 235         .crvalidate     = unx_validate,
 236 };