FreeBSD/Linux Kernel Cross Reference
sys/fs/nfsclient/nfs_clkrpc.c

     /*-
      * SPDX-License-Identifier: BSD-3-Clause
      *
      * Copyright (c) 1989, 1993
      *      The Regents of the University of California.  All rights reserved.
      *
      * This code is derived from software contributed to Berkeley by
      * Rick Macklem at The University of Guelph.
      *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include "opt_kgssapi.h"
    #include "opt_kern_tls.h"
    
    #include <fs/nfs/nfsport.h>
    
    #include <rpc/rpc.h>
    #include <rpc/replay.h>
    #include <rpc/rpcsec_gss.h>
    #include <rpc/rpcsec_tls.h>
    
    NFSDLOCKMUTEX;
    
    extern SVCPOOL  *nfscbd_pool;
    
    static int nfs_cbproc(struct nfsrv_descript *, u_int32_t);
    
    extern u_long sb_max_adj;
    extern int nfs_numnfscbd;
    extern int nfscl_debuglevel;
    
    /*
     * NFS client system calls for handling callbacks.
     */
    
    /*
     * Handles server to client callbacks.
     */
    static void
    nfscb_program(struct svc_req *rqst, SVCXPRT *xprt)
    {
            struct nfsrv_descript nd;
            int cacherep, credflavor;
    #ifdef KERN_TLS
            u_int maxlen;
    #endif
    
            memset(&nd, 0, sizeof(nd));
            if (rqst->rq_proc != NFSPROC_NULL &&
                rqst->rq_proc != NFSV4PROC_CBCOMPOUND) {
                    svcerr_noproc(rqst);
                    svc_freereq(rqst);
                    return;
            }
            nd.nd_procnum = rqst->rq_proc;
            nd.nd_flag = (ND_NFSCB | ND_NFSV4);
    
            /*
             * Note: we want rq_addr, not svc_getrpccaller for nd_nam2 -
             * NFS_SRVMAXDATA uses a NULL value for nd_nam2 to detect TCP
             * mounts.
             */
            nd.nd_mrep = rqst->rq_args;
            rqst->rq_args = NULL;
            newnfs_realign(&nd.nd_mrep, M_WAITOK);
            nd.nd_md = nd.nd_mrep;
            nd.nd_dpos = mtod(nd.nd_md, caddr_t);
            nd.nd_nam = svc_getrpccaller(rqst);
            nd.nd_nam2 = rqst->rq_addr;
            nd.nd_mreq = NULL;
            nd.nd_cred = NULL;
    
           NFSCL_DEBUG(1, "cbproc=%d\n",nd.nd_procnum);
           if (nd.nd_procnum != NFSPROC_NULL) {
                   if (!svc_getcred(rqst, &nd.nd_cred, &credflavor)) {
                           svcerr_weakauth(rqst);
                           svc_freereq(rqst);
                           m_freem(nd.nd_mrep);
                           return;
                   }
   
                   /* For now, I don't care what credential flavor was used. */
   #ifdef notyet
   #ifdef MAC
                   mac_cred_associate_nfsd(nd.nd_cred);
   #endif
   #endif
   #ifdef KERN_TLS
                   if ((xprt->xp_tls & RPCTLS_FLAGS_HANDSHAKE) != 0 &&
                       rpctls_getinfo(&maxlen, false, false)) {
                           nd.nd_flag |= ND_EXTPG;
                           nd.nd_maxextsiz = maxlen;
                   }
   #endif
                   cacherep = nfs_cbproc(&nd, rqst->rq_xid);
           } else {
                   NFSMGET(nd.nd_mreq);
                   nd.nd_mreq->m_len = 0;
                   cacherep = RC_REPLY;
           }
           if (nd.nd_mrep != NULL)
                   m_freem(nd.nd_mrep);
   
           if (nd.nd_cred != NULL)
                   crfree(nd.nd_cred);
   
           if (cacherep == RC_DROPIT) {
                   if (nd.nd_mreq != NULL)
                           m_freem(nd.nd_mreq);
                   svc_freereq(rqst);
                   return;
           }
   
           if (nd.nd_mreq == NULL) {
                   svcerr_decode(rqst);
                   svc_freereq(rqst);
                   return;
           }
   
           if (nd.nd_repstat & NFSERR_AUTHERR) {
                   svcerr_auth(rqst, nd.nd_repstat & ~NFSERR_AUTHERR);
                   if (nd.nd_mreq != NULL)
                           m_freem(nd.nd_mreq);
           } else if (!svc_sendreply_mbuf(rqst, nd.nd_mreq))
                   svcerr_systemerr(rqst);
           else
                   NFSCL_DEBUG(1, "cbrep sent\n");
           svc_freereq(rqst);
   }
   
   /*
    * Check the cache and, optionally, do the RPC.
    * Return the appropriate cache response.
    */
   static int
   nfs_cbproc(struct nfsrv_descript *nd, u_int32_t xid)
   {
           struct thread *td = curthread;
           int cacherep;
   
           if (nd->nd_nam2 == NULL)
                   nd->nd_flag |= ND_STREAMSOCK;
   
           nfscl_docb(nd, td);
           if (nd->nd_repstat == NFSERR_DONTREPLY)
                   cacherep = RC_DROPIT;
           else
                   cacherep = RC_REPLY;
           return (cacherep);
   }
   
   /*
    * Adds a socket to the list for servicing by nfscbds.
    */
   int
   nfscbd_addsock(struct file *fp)
   {
           int siz;
           struct socket *so;
           int error;
           SVCXPRT *xprt;
   
           so = fp->f_data;
   
           siz = sb_max_adj;
           error = soreserve(so, siz, siz);
           if (error)
                   return (error);
   
           /*
            * Steal the socket from userland so that it doesn't close
            * unexpectedly.
            */
           if (so->so_type == SOCK_DGRAM)
                   xprt = svc_dg_create(nfscbd_pool, so, 0, 0);
           else
                   xprt = svc_vc_create(nfscbd_pool, so, 0, 0);
           if (xprt) {
                   fp->f_ops = &badfileops;
                   fp->f_data = NULL;
                   svc_reg(xprt, NFS_CALLBCKPROG, NFSV4_CBVERS, nfscb_program,
                       NULL);
                   SVC_RELEASE(xprt);
           }
   
           return (0);
   }
   
   /*
    * Called by nfssvc() for nfscbds. Just loops around servicing rpc requests
    * until it is killed by a signal.
    *
    * For now, only support callbacks via RPCSEC_GSS if there is a KerberosV
    * keytab entry with a host based entry in it on the client. (I'm not even
    * sure that getting Acceptor credentials for a user principal with a
    * credentials cache is possible, but even if it is, major changes to the
    * kgssapi would be required.)
    * I don't believe that this is a serious limitation since, as of 2009, most
    * NFSv4 servers supporting callbacks are using AUTH_SYS for callbacks even
    * when the client is using RPCSEC_GSS. (This BSD server uses AUTH_SYS
    * for callbacks unless nfsrv_gsscallbackson is set non-zero.)
    */
   int
   nfscbd_nfsd(struct thread *td, struct nfsd_nfscbd_args *args)
   {
           char principal[128];
           int error;
   
           if (args != NULL) {
                   error = copyinstr(args->principal, principal,
                       sizeof(principal), NULL);
                   if (error)
                           return (error);
           } else {
                   principal[0] = '\0';
           }
   
           /*
            * Only the first nfsd actually does any work. The RPC code
            * adds threads to it as needed. Any extra processes offered
            * by nfsd just exit. If nfsd is new enough, it will call us
            * once with a structure that specifies how many threads to
            * use.
            */
           NFSD_LOCK();
           if (nfs_numnfscbd == 0) {
                   nfs_numnfscbd++;
   
                   NFSD_UNLOCK();
   
                   if (principal[0] != '\0')
                           rpc_gss_set_svc_name_call(principal, "kerberosv5",
                               GSS_C_INDEFINITE, NFS_CALLBCKPROG, NFSV4_CBVERS);
   
                   nfscbd_pool->sp_minthreads = 4;
                   nfscbd_pool->sp_maxthreads = 4;
                           
                   svc_run(nfscbd_pool);
   
                   rpc_gss_clear_svc_name_call(NFS_CALLBCKPROG, NFSV4_CBVERS);
   
                   NFSD_LOCK();
                   nfs_numnfscbd--;
                   nfsrvd_cbinit(1);
           }
           NFSD_UNLOCK();
   
           return (0);
   }
   
   /*
    * Initialize the data structures for the server.
    * Handshake with any new nfsds starting up to avoid any chance of
    * corruption.
    */
   void
   nfsrvd_cbinit(int terminating)
   {
   
           NFSD_LOCK_ASSERT();
   
           if (terminating) {
                   /* Wait for any xprt registrations to complete. */
                   while (nfs_numnfscbd > 0)
                           msleep(&nfs_numnfscbd, NFSDLOCKMUTEXPTR, PZERO, 
                               "nfscbdt", 0);
                   if (nfscbd_pool != NULL) {
                           NFSD_UNLOCK();
                           svcpool_close(nfscbd_pool);
                           NFSD_LOCK();
                   }
           }
   
           if (nfscbd_pool == NULL) {
                   NFSD_UNLOCK();
                   nfscbd_pool = svcpool_create("nfscbd", NULL);
                   nfscbd_pool->sp_rcache = NULL;
                   nfscbd_pool->sp_assign = NULL;
                   nfscbd_pool->sp_done = NULL;
                   NFSD_LOCK();
           }
   }

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