net/sunrpc/auth_unix.c

   1 /*
   2  * linux/net/sunrpc/rpcauth_unix.c
   3  *
   4  * UNIX-style authentication; no AUTH_SHORT support
   5  *
   6  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
   7  *
   8  * Modified May 1999 Horst von Brand <vonbrand@sleipnir.valparaiso.cl>
   9  */
  10
  11 #include <linux/types.h>
  12 #include <linux/string.h>
  13 #include <linux/malloc.h>
  14 #include <linux/socket.h>
  15 #include <linux/in.h>
  16 #include <linux/sunrpc/clnt.h>
  17 #include <linux/sunrpc/auth.h>
  18
  19 #define NFS_NGROUPS     16
  20 struct unx_cred {
  21         struct rpc_cred         uc_base;
  22         uid_t                   uc_fsuid;
  23         gid_t                   uc_gid, uc_fsgid;
  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_auth *
  40 unx_create(struct rpc_clnt *clnt)
  41 {
  42         struct rpc_auth *auth;
  43
  44         dprintk("RPC: creating UNIX authenticator for client %p\n", clnt);
  45         if (!(auth = (struct rpc_auth *) rpc_allocate(0, sizeof(*auth))))
  46                 return NULL;
  47         auth->au_cslack = UNX_WRITESLACK;
  48         auth->au_rslack = 2;    /* assume AUTH_NULL verf */
  49         auth->au_expire = UNX_CRED_EXPIRE;
  50         auth->au_ops = &authunix_ops;
  51
  52         rpcauth_init_credcache(auth);
  53
  54         return auth;
  55 }
  56
  57 static void
  58 unx_destroy(struct rpc_auth *auth)
  59 {
  60         dprintk("RPC: destroying UNIX authenticator %p\n", auth);
  61         rpcauth_free_credcache(auth);
  62         rpc_free(auth);
  63 }
  64
  65 static struct rpc_cred *
  66 unx_create_cred(struct rpc_task *task)
  67 {
  68         struct unx_cred *cred;
  69         int             i;
  70
  71         dprintk("RPC:      allocating UNIX cred for uid %d gid %d\n",
  72                                 current->uid, current->gid);
  73
  74         if (!(cred = (struct unx_cred *) rpc_malloc(task, sizeof(*cred)))) {
  75                 task->tk_status = -ENOMEM;
  76                 return NULL;
  77         }
  78
  79         cred->uc_count = 0;
  80         cred->uc_flags = RPCAUTH_CRED_UPTODATE;
  81         if (RPC_DO_ROOTOVERRIDE(task)) {
  82                 cred->uc_uid = cred->uc_fsuid = 0;
  83                 cred->uc_gid = cred->uc_fsgid = 0;
  84                 cred->uc_gids[0] = NOGROUP;
  85         } else {
  86                 int groups = current->ngroups;
  87                 if (groups > NFS_NGROUPS)
  88                         groups = NFS_NGROUPS;
  89
  90                 cred->uc_uid = current->uid;
  91                 cred->uc_gid = current->gid;
  92                 cred->uc_fsuid = current->fsuid;
  93                 cred->uc_fsgid = current->fsgid;
  94                 for (i = 0; i < groups; i++)
  95                         cred->uc_gids[i] = (gid_t) current->groups[i];
  96                 if (i < NFS_NGROUPS)
  97                   cred->uc_gids[i] = NOGROUP;
  98         }
  99
 100         return (struct rpc_cred *) cred;
 101 }
 102
 103 struct rpc_cred *
 104 authunix_fake_cred(struct rpc_task *task, uid_t uid, gid_t gid)
 105 {
 106         struct unx_cred *cred;
 107
 108         dprintk("RPC:      allocating fake UNIX cred for uid %d gid %d\n",
 109                                 uid, gid);
 110
 111         if (!(cred = (struct unx_cred *) rpc_malloc(task, sizeof(*cred))))
 112                 return NULL;
 113
 114         cred->uc_count = 1;
 115         cred->uc_flags = RPCAUTH_CRED_DEAD|RPCAUTH_CRED_UPTODATE;
 116         cred->uc_uid   = uid;
 117         cred->uc_gid   = gid;
 118         cred->uc_fsuid = uid;
 119         cred->uc_fsgid = gid;
 120         cred->uc_gids[0] = (gid_t) NOGROUP;
 121
 122         return task->tk_cred = (struct rpc_cred *) cred;
 123 }
 124
 125 static void
 126 unx_destroy_cred(struct rpc_cred *cred)
 127 {
 128         rpc_free(cred);
 129 }
 130
 131 /*
 132  * Match credentials against current process creds.
 133  * The root_override argument takes care of cases where the caller may
 134  * request root creds (e.g. for NFS swapping).
 135  */
 136 static int
 137 unx_match(struct rpc_task * task, struct rpc_cred *rcred)
 138 {
 139         struct unx_cred *cred = (struct unx_cred *) rcred;
 140         int             i;
 141
 142         if (!RPC_DO_ROOTOVERRIDE(task)) {
 143                 int groups;
 144
 145                 if (cred->uc_uid != current->uid
 146                  || cred->uc_gid != current->gid
 147                  || cred->uc_fsuid != current->fsuid
 148                  || cred->uc_fsgid != current->fsgid)
 149                         return 0;
 150
 151                 groups = current->ngroups;
 152                 if (groups > NFS_NGROUPS)
 153                         groups = NFS_NGROUPS;
 154                 for (i = 0; i < groups ; i++)
 155                         if (cred->uc_gids[i] != (gid_t) current->groups[i])
 156                                 return 0;
 157                 return 1;
 158         }
 159         return (cred->uc_uid == 0 && cred->uc_fsuid == 0
 160              && cred->uc_gid == 0 && cred->uc_fsgid == 0
 161              && cred->uc_gids[0] == (gid_t) NOGROUP);
 162 }
 163
 164 /*
 165  * Marshal credentials.
 166  * Maybe we should keep a cached credential for performance reasons.
 167  */
 168 static u32 *
 169 unx_marshal(struct rpc_task *task, u32 *p, int ruid)
 170 {
 171         struct rpc_clnt *clnt = task->tk_client;
 172         struct unx_cred *cred = (struct unx_cred *) task->tk_cred;
 173         u32             *base, *hold;
 174         int             i, n;
 175
 176         *p++ = htonl(RPC_AUTH_UNIX);
 177         base = p++;
 178         *p++ = htonl(jiffies/HZ);
 179
 180         /*
 181          * Copy the UTS nodename captured when the client was created.
 182          */
 183         n = clnt->cl_nodelen;
 184         *p++ = htonl(n);
 185         memcpy(p, clnt->cl_nodename, n);
 186         p += (n + 3) >> 2;
 187
 188         if (ruid) {
 189                 *p++ = htonl((u32) cred->uc_uid);
 190                 *p++ = htonl((u32) cred->uc_gid);
 191         } else {
 192                 *p++ = htonl((u32) cred->uc_fsuid);
 193                 *p++ = htonl((u32) cred->uc_fsgid);
 194         }
 195         hold = p++;
 196         for (i = 0; i < 16 && cred->uc_gids[i] != (gid_t) NOGROUP; i++)
 197                 *p++ = htonl((u32) cred->uc_gids[i]);
 198         *hold = htonl(p - hold - 1);            /* gid array length */
 199         *base = htonl((p - base - 1) << 2);     /* cred length */
 200
 201         *p++ = htonl(RPC_AUTH_NULL);
 202         *p++ = htonl(0);
 203
 204         return p;
 205 }
 206
 207 /*
 208  * Refresh credentials. This is a no-op for AUTH_UNIX
 209  */
 210 static int
 211 unx_refresh(struct rpc_task *task)
 212 {
 213         task->tk_cred->cr_flags |= RPCAUTH_CRED_UPTODATE;
 214         return task->tk_status = -EACCES;
 215 }
 216
 217 static u32 *
 218 unx_validate(struct rpc_task *task, u32 *p)
 219 {
 220         u32             n = ntohl(*p++);
 221
 222         if (n != RPC_AUTH_NULL && n != RPC_AUTH_UNIX && n != RPC_AUTH_SHORT) {
 223                 printk("RPC: bad verf flavor: %ld\n", (unsigned long) n);
 224                 return NULL;
 225         }
 226         if ((n = ntohl(*p++)) > 400) {
 227                 printk("RPC: giant verf size: %ld\n", (unsigned long) n);
 228                 return NULL;
 229         }
 230         task->tk_auth->au_rslack = (n >> 2) + 2;
 231         p += (n >> 2);
 232
 233         return p;
 234 }
 235
 236 struct rpc_authops      authunix_ops = {
 237         RPC_AUTH_UNIX,
 238 #ifdef RPC_DEBUG
 239         "UNIX",
 240 #endif
 241         unx_create,
 242         unx_destroy,
 243         unx_create_cred,
 244         unx_destroy_cred,
 245         unx_match,
 246         unx_marshal,
 247         unx_refresh,
 248         unx_validate
 249 };