fs/nfs/callback.c

   1 /*
   2  * linux/fs/nfs/callback.c
   3  *
   4  * Copyright (C) 2004 Trond Myklebust
   5  *
   6  * NFSv4 callback handling
   7  */
   8
   9 #include <linux/config.h>
  10 #include <linux/completion.h>
  11 #include <linux/ip.h>
  12 #include <linux/module.h>
  13 #include <linux/smp_lock.h>
  14 #include <linux/sunrpc/svc.h>
  15 #include <linux/sunrpc/svcsock.h>
  16 #include <linux/nfs_fs.h>
  17 #include "callback.h"
  18
  19 #define NFSDBG_FACILITY NFSDBG_CALLBACK
  20
  21 struct nfs_callback_data {
  22         unsigned int users;
  23         struct svc_serv *serv;
  24         pid_t pid;
  25         struct completion started;
  26         struct completion stopped;
  27 };
  28
  29 static struct nfs_callback_data nfs_callback_info;
  30 static DECLARE_MUTEX(nfs_callback_sema);
  31 static struct svc_program nfs4_callback_program;
  32
  33 unsigned short nfs_callback_tcpport;
  34
  35 /*
  36  * This is the callback kernel thread.
  37  */
  38 static void nfs_callback_svc(struct svc_rqst *rqstp)
  39 {
  40         struct svc_serv *serv = rqstp->rq_server;
  41         int err;
  42
  43         __module_get(THIS_MODULE);
  44         lock_kernel();
  45
  46         nfs_callback_info.pid = current->pid;
  47         daemonize("nfsv4-svc");
  48         /* Process request with signals blocked, but allow SIGKILL.  */
  49         allow_signal(SIGKILL);
  50
  51         complete(&nfs_callback_info.started);
  52
  53         while (nfs_callback_info.users != 0 || !signalled()) {
  54                 /*
  55                  * Listen for a request on the socket
  56                  */
  57                 err = svc_recv(serv, rqstp, MAX_SCHEDULE_TIMEOUT);
  58                 if (err == -EAGAIN || err == -EINTR)
  59                         continue;
  60                 if (err < 0) {
  61                         printk(KERN_WARNING
  62                                         "%s: terminating on error %d\n",
  63                                         __FUNCTION__, -err);
  64                         break;
  65                 }
  66                 dprintk("%s: request from %u.%u.%u.%u\n", __FUNCTION__,
  67                                 NIPQUAD(rqstp->rq_addr.sin_addr.s_addr));
  68                 svc_process(serv, rqstp);
  69         }
  70
  71         nfs_callback_info.pid = 0;
  72         complete(&nfs_callback_info.stopped);
  73         unlock_kernel();
  74         module_put_and_exit(0);
  75 }
  76
  77 /*
  78  * Bring up the server process if it is not already up.
  79  */
  80 int nfs_callback_up(void)
  81 {
  82         struct svc_serv *serv;
  83         struct svc_sock *svsk;
  84         int ret = 0;
  85
  86         lock_kernel();
  87         down(&nfs_callback_sema);
  88         if (nfs_callback_info.users++ || nfs_callback_info.pid != 0)
  89                 goto out;
  90         init_completion(&nfs_callback_info.started);
  91         init_completion(&nfs_callback_info.stopped);
  92         serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE);
  93         ret = -ENOMEM;
  94         if (!serv)
  95                 goto out_err;
  96         /* FIXME: We don't want to register this socket with the portmapper */
  97         ret = svc_makesock(serv, IPPROTO_TCP, 0);
  98         if (ret < 0)
  99                 goto out_destroy;
 100         if (!list_empty(&serv->sv_permsocks)) {
 101                 svsk = list_entry(serv->sv_permsocks.next,
 102                                 struct svc_sock, sk_list);
 103                 nfs_callback_tcpport = ntohs(inet_sk(svsk->sk_sk)->sport);
 104                 dprintk ("Callback port = 0x%x\n", nfs_callback_tcpport);
 105         } else
 106                 BUG();
 107         ret = svc_create_thread(nfs_callback_svc, serv);
 108         if (ret < 0)
 109                 goto out_destroy;
 110         nfs_callback_info.serv = serv;
 111         wait_for_completion(&nfs_callback_info.started);
 112 out:
 113         up(&nfs_callback_sema);
 114         unlock_kernel();
 115         return ret;
 116 out_destroy:
 117         svc_destroy(serv);
 118 out_err:
 119         nfs_callback_info.users--;
 120         goto out;
 121 }
 122
 123 /*
 124  * Kill the server process if it is not already up.
 125  */
 126 int nfs_callback_down(void)
 127 {
 128         int ret = 0;
 129
 130         lock_kernel();
 131         down(&nfs_callback_sema);
 132         if (--nfs_callback_info.users || nfs_callback_info.pid == 0)
 133                 goto out;
 134         kill_proc(nfs_callback_info.pid, SIGKILL, 1);
 135         wait_for_completion(&nfs_callback_info.stopped);
 136 out:
 137         up(&nfs_callback_sema);
 138         unlock_kernel();
 139         return ret;
 140 }
 141
 142 /*
 143  * AUTH_NULL authentication
 144  */
 145 static int nfs_callback_null_accept(struct svc_rqst *rqstp, u32 *authp)
 146 {
 147         struct kvec    *argv = &rqstp->rq_arg.head[0];
 148         struct kvec    *resv = &rqstp->rq_res.head[0];
 149
 150         if (argv->iov_len < 3*4)
 151                 return SVC_GARBAGE;
 152
 153         if (svc_getu32(argv) != 0) {
 154                 dprintk("svc: bad null cred\n");
 155                 *authp = rpc_autherr_badcred;
 156                 return SVC_DENIED;
 157         }
 158         if (svc_getu32(argv) != RPC_AUTH_NULL || svc_getu32(argv) != 0) {
 159                 dprintk("svc: bad null verf\n");
 160                  *authp = rpc_autherr_badverf;
 161                  return SVC_DENIED;
 162         }
 163
 164         /* Signal that mapping to nobody uid/gid is required */
 165         rqstp->rq_cred.cr_uid = (uid_t) -1;
 166         rqstp->rq_cred.cr_gid = (gid_t) -1;
 167         rqstp->rq_cred.cr_group_info = groups_alloc(0);
 168         if (rqstp->rq_cred.cr_group_info == NULL)
 169                 return SVC_DROP; /* kmalloc failure - client must retry */
 170
 171         /* Put NULL verifier */
 172         svc_putu32(resv, RPC_AUTH_NULL);
 173         svc_putu32(resv, 0);
 174         dprintk("%s: success, returning %d!\n", __FUNCTION__, SVC_OK);
 175         return SVC_OK;
 176 }
 177
 178 static int nfs_callback_null_release(struct svc_rqst *rqstp)
 179 {
 180         if (rqstp->rq_cred.cr_group_info)
 181                 put_group_info(rqstp->rq_cred.cr_group_info);
 182         rqstp->rq_cred.cr_group_info = NULL;
 183         return 0; /* don't drop */
 184 }
 185
 186 static struct auth_ops nfs_callback_auth_null = {
 187         .name = "null",
 188         .flavour = RPC_AUTH_NULL,
 189         .accept = nfs_callback_null_accept,
 190         .release = nfs_callback_null_release,
 191 };
 192
 193 /*
 194  * AUTH_SYS authentication
 195  */
 196 static int nfs_callback_unix_accept(struct svc_rqst *rqstp, u32 *authp)
 197 {
 198         struct kvec    *argv = &rqstp->rq_arg.head[0];
 199         struct kvec    *resv = &rqstp->rq_res.head[0];
 200         struct svc_cred *cred = &rqstp->rq_cred;
 201         u32 slen, i;
 202         int len = argv->iov_len;
 203
 204         dprintk("%s: start\n", __FUNCTION__);
 205         cred->cr_group_info = NULL;
 206         rqstp->rq_client = NULL;
 207         if ((len -= 3*4) < 0)
 208                 return SVC_GARBAGE;
 209
 210         /* Get length, time stamp and machine name */
 211         svc_getu32(argv);
 212         svc_getu32(argv);
 213         slen = XDR_QUADLEN(ntohl(svc_getu32(argv)));
 214         if (slen > 64 || (len -= (slen + 3)*4) < 0)
 215                 goto badcred;
 216         argv->iov_base = (void*)((u32*)argv->iov_base + slen);
 217         argv->iov_len -= slen*4;
 218
 219         cred->cr_uid = ntohl(svc_getu32(argv));
 220         cred->cr_gid = ntohl(svc_getu32(argv));
 221         slen = ntohl(svc_getu32(argv));
 222         if (slen > 16 || (len -= (slen + 2)*4) < 0)
 223                 goto badcred;
 224         cred->cr_group_info = groups_alloc(slen);
 225         if (cred->cr_group_info == NULL)
 226                 return SVC_DROP;
 227         for (i = 0; i < slen; i++)
 228                 GROUP_AT(cred->cr_group_info, i) = ntohl(svc_getu32(argv));
 229
 230         if (svc_getu32(argv) != RPC_AUTH_NULL || svc_getu32(argv) != 0) {
 231                 *authp = rpc_autherr_badverf;
 232                 return SVC_DENIED;
 233         }
 234         /* Put NULL verifier */
 235         svc_putu32(resv, RPC_AUTH_NULL);
 236         svc_putu32(resv, 0);
 237         dprintk("%s: success, returning %d!\n", __FUNCTION__, SVC_OK);
 238         return SVC_OK;
 239 badcred:
 240         *authp = rpc_autherr_badcred;
 241         return SVC_DENIED;
 242 }
 243
 244 static int nfs_callback_unix_release(struct svc_rqst *rqstp)
 245 {
 246         if (rqstp->rq_cred.cr_group_info)
 247                 put_group_info(rqstp->rq_cred.cr_group_info);
 248         rqstp->rq_cred.cr_group_info = NULL;
 249         return 0;
 250 }
 251
 252 static struct auth_ops nfs_callback_auth_unix = {
 253         .name = "unix",
 254         .flavour = RPC_AUTH_UNIX,
 255         .accept = nfs_callback_unix_accept,
 256         .release = nfs_callback_unix_release,
 257 };
 258
 259 /*
 260  * Hook the authentication protocol
 261  */
 262 static int nfs_callback_auth(struct svc_rqst *rqstp, u32 *authp)
 263 {
 264         struct in_addr *addr = &rqstp->rq_addr.sin_addr;
 265         struct nfs4_client *clp;
 266         struct kvec *argv = &rqstp->rq_arg.head[0];
 267         int flavour;
 268         int retval;
 269
 270         /* Don't talk to strangers */
 271         clp = nfs4_find_client(addr);
 272         if (clp == NULL)
 273                 return SVC_DROP;
 274         dprintk("%s: %u.%u.%u.%u NFSv4 callback!\n", __FUNCTION__, NIPQUAD(addr));
 275         nfs4_put_client(clp);
 276         flavour = ntohl(svc_getu32(argv));
 277         switch(flavour) {
 278                 case RPC_AUTH_NULL:
 279                         if (rqstp->rq_proc != CB_NULL) {
 280                                 *authp = rpc_autherr_tooweak;
 281                                 retval = SVC_DENIED;
 282                                 break;
 283                         }
 284                         rqstp->rq_authop = &nfs_callback_auth_null;
 285                         retval = nfs_callback_null_accept(rqstp, authp);
 286                         break;
 287                 case RPC_AUTH_UNIX:
 288                         /* Eat the authentication flavour */
 289                         rqstp->rq_authop = &nfs_callback_auth_unix;
 290                         retval = nfs_callback_unix_accept(rqstp, authp);
 291                         break;
 292                 default:
 293                         /* FIXME: need to add RPCSEC_GSS upcalls */
 294 #if 0
 295                         svc_ungetu32(argv);
 296                         retval = svc_authenticate(rqstp, authp);
 297 #else
 298                         *authp = rpc_autherr_rejectedcred;
 299                         retval = SVC_DENIED;
 300 #endif
 301         }
 302         dprintk("%s: flavour %d returning error %d\n", __FUNCTION__, flavour, retval);
 303         return retval;
 304 }
 305
 306 /*
 307  * Define NFS4 callback program
 308  */
 309 extern struct svc_version nfs4_callback_version1;
 310
 311 static struct svc_version *nfs4_callback_version[] = {
 312         [1] = &nfs4_callback_version1,
 313 };
 314
 315 static struct svc_stat nfs4_callback_stats;
 316
 317 static struct svc_program nfs4_callback_program = {
 318         .pg_prog = NFS4_CALLBACK,                       /* RPC service number */
 319         .pg_nvers = ARRAY_SIZE(nfs4_callback_version),  /* Number of entries */
 320         .pg_vers = nfs4_callback_version,               /* version table */
 321         .pg_name = "NFSv4 callback",                    /* service name */
 322         .pg_class = "nfs",                              /* authentication class */
 323         .pg_stats = &nfs4_callback_stats,
 324         .pg_authenticate = nfs_callback_auth,
 325 };