/*      $NetBSD: nfs_nfsdkrpc.c,v 1.5 2024/07/05 04:31:52 rin Exp $     */
/*-
 * 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.
 * 4. 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: head/sys/fs/nfsserver/nfs_nfsdkrpc.c 299203 2016-05-06 23:40:37Z pfg "); */
__RCSID("$NetBSD: nfs_nfsdkrpc.c,v 1.5 2024/07/05 04:31:52 rin Exp $");

#ifdef _KERNEL_OPT
#include "opt_inet6.h"
#if 0
#include "opt_kgssapi.h"
#endif
#endif

#include <fs/nfs/common/nfsport.h>

#include <rpc/rpc.h>
#include <rpc/rpcsec_gss.h>

#include <fs/nfs/common/nfs_fha.h>
#include <fs/nfs/server/nfs_fha_new.h>

#if 0
#include <security/mac/mac_framework.h>
#endif

NFSDLOCKMUTEX;
NFSV4ROOTLOCKMUTEX;
struct nfsv4lock nfsd_suspend_lock;

/*
 * Mapping of old NFS Version 2 RPC numbers to generic numbers.
 */
int newnfs_nfsv3_procid[NFS_V3NPROCS] = {
        NFSPROC_NULL,
        NFSPROC_GETATTR,
        NFSPROC_SETATTR,
        NFSPROC_NOOP,
        NFSPROC_LOOKUP,
        NFSPROC_READLINK,
        NFSPROC_READ,
        NFSPROC_NOOP,
        NFSPROC_WRITE,
        NFSPROC_CREATE,
        NFSPROC_REMOVE,
        NFSPROC_RENAME,
        NFSPROC_LINK,
        NFSPROC_SYMLINK,
        NFSPROC_MKDIR,
        NFSPROC_RMDIR,
        NFSPROC_READDIR,
        NFSPROC_FSSTAT,
        NFSPROC_NOOP,
        NFSPROC_NOOP,
        NFSPROC_NOOP,
        NFSPROC_NOOP,
};


SYSCTL_DECL(_vfs_nfsd);

SVCPOOL         *nfsrvd_pool;

static int      nfs_privport = 0;
SYSCTL_INT(_vfs_nfsd, OID_AUTO, nfs_privport, CTLFLAG_RWTUN,
    &nfs_privport, 0,
    "Only allow clients using a privileged port for NFSv2 and 3");

static int      nfs_minvers = NFS_VER2;
SYSCTL_INT(_vfs_nfsd, OID_AUTO, server_min_nfsvers, CTLFLAG_RWTUN,
    &nfs_minvers, 0, "The lowest version of NFS handled by the server");

static int      nfs_maxvers = NFS_VER4;
SYSCTL_INT(_vfs_nfsd, OID_AUTO, server_max_nfsvers, CTLFLAG_RWTUN,
    &nfs_maxvers, 0, "The highest version of NFS handled by the server");

static int nfs_proc(struct nfsrv_descript *, u_int32_t, SVCXPRT *xprt,
    struct nfsrvcache **);

extern u_long sb_max_adj;
extern int newnfs_numnfsd;
extern struct proc *nfsd_master_proc;

/*
 * NFS server system calls
 */

static void
nfssvc_program(struct svc_req *rqst, SVCXPRT *xprt)
{
        struct nfsrv_descript nd;
        struct nfsrvcache *rp = NULL;
        int cacherep, credflavor;

        memset(&nd, 0, sizeof(nd));
        if (rqst->rq_vers == NFS_VER2) {
                if (rqst->rq_proc > NFSV2PROC_STATFS ||
                    newnfs_nfsv3_procid[rqst->rq_proc] == NFSPROC_NOOP) {
                        svcerr_noproc(rqst);
                        svc_freereq(rqst);
                        goto out;
                }
                nd.nd_procnum = newnfs_nfsv3_procid[rqst->rq_proc];
                nd.nd_flag = ND_NFSV2;
        } else if (rqst->rq_vers == NFS_VER3) {
                if (rqst->rq_proc >= NFS_V3NPROCS) {
                        svcerr_noproc(rqst);
                        svc_freereq(rqst);
                        goto out;
                }
                nd.nd_procnum = rqst->rq_proc;
                nd.nd_flag = ND_NFSV3;
        } else {
                if (rqst->rq_proc != NFSPROC_NULL &&
                    rqst->rq_proc != NFSV4PROC_COMPOUND) {
                        svcerr_noproc(rqst);
                        svc_freereq(rqst);
                        goto out;
                }
                nd.nd_procnum = rqst->rq_proc;
                nd.nd_flag = 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;

        if (nfs_privport && (nd.nd_flag & ND_NFSV4) == 0) {
                /* Check if source port is privileged */
                u_short port;
                struct sockaddr *nam = nd.nd_nam;
                struct sockaddr_in *sin;

                sin = (struct sockaddr_in *)nam;
                /*
                 * INET/INET6 - same code:
                 *    sin_port and sin6_port are at same offset
                 */
                port = ntohs(sin->sin_port);
                if (port >= IPPORT_RESERVED &&
                    nd.nd_procnum != NFSPROC_NULL) {
#ifdef INET6
                        char b6[INET6_ADDRSTRLEN];
#if defined(_MODULE)
                        /* Do not use ip6_sprintf: the nfs module should work without INET6. */
#define ip6_sprintf(buf, a)                                             \
                        (snprintf((buf), sizeof(buf), "%x:%x:%x:%x:%x:%x:%x:%x",        \
                            (a)->s6_addr16[0], (a)->s6_addr16[1],       \
                            (a)->s6_addr16[2], (a)->s6_addr16[3],       \
                            (a)->s6_addr16[4], (a)->s6_addr16[5],       \
                            (a)->s6_addr16[6], (a)->s6_addr16[7]),      \
                            (buf))
#endif
#endif
                        printf("NFS request from unprivileged port (%s:%d)\n",
#ifdef INET6
                            sin->sin_family == AF_INET6 ?
                            ip6_sprintf(b6, &satosin6(sin)->sin6_addr) :
#if defined(_MODULE)
#undef ip6_sprintf
#endif
#endif
                            inet_ntoa(sin->sin_addr), port);
                        svcerr_weakauth(rqst);
                        svc_freereq(rqst);
                        m_freem(nd.nd_mrep);
                        goto out;
                }
        }

        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);
                        goto out;
                }

                /* Set the flag based on credflavor */
                if (credflavor == RPCSEC_GSS_KRB5) {
                        nd.nd_flag |= ND_GSS;
                } else if (credflavor == RPCSEC_GSS_KRB5I) {
                        nd.nd_flag |= (ND_GSS | ND_GSSINTEGRITY);
                } else if (credflavor == RPCSEC_GSS_KRB5P) {
                        nd.nd_flag |= (ND_GSS | ND_GSSPRIVACY);
                } else if (credflavor != AUTH_SYS) {
                        svcerr_weakauth(rqst);
                        svc_freereq(rqst);
                        m_freem(nd.nd_mrep);
                        goto out;
                }

#ifdef MAC
                mac_cred_associate_nfsd(nd.nd_cred);
#endif
                /*
                 * Get a refcnt (shared lock) on nfsd_suspend_lock.
                 * NFSSVC_SUSPENDNFSD will take an exclusive lock on
                 * nfsd_suspend_lock to suspend these threads.
                 * The call to nfsv4_lock() that precedes nfsv4_getref()
                 * ensures that the acquisition of the exclusive lock
                 * takes priority over acquisition of the shared lock by
                 * waiting for any exclusive lock request to complete.
                 * This must be done here, before the check of
                 * nfsv4root exports by nfsvno_v4rootexport().
                 */
                NFSLOCKV4ROOTMUTEX();
                nfsv4_lock(&nfsd_suspend_lock, 0, NULL, NFSV4ROOTLOCKMUTEXPTR,
                    NULL);
                nfsv4_getref(&nfsd_suspend_lock, NULL, NFSV4ROOTLOCKMUTEXPTR,
                    NULL);
                NFSUNLOCKV4ROOTMUTEX();

                if ((nd.nd_flag & ND_NFSV4) != 0) {
                        nd.nd_repstat = nfsvno_v4rootexport(&nd);
                        if (nd.nd_repstat != 0) {
                                NFSLOCKV4ROOTMUTEX();
                                nfsv4_relref(&nfsd_suspend_lock);
                                NFSUNLOCKV4ROOTMUTEX();
                                svcerr_weakauth(rqst);
                                svc_freereq(rqst);
                                m_freem(nd.nd_mrep);
                                goto out;
                        }
                }

                cacherep = nfs_proc(&nd, rqst->rq_xid, xprt, &rp);
                NFSLOCKV4ROOTMUTEX();
                nfsv4_relref(&nfsd_suspend_lock);
                NFSUNLOCKV4ROOTMUTEX();
        } else {
                NFSMGET(nd.nd_mreq);
                nd.nd_mreq->m_len = 0;
                cacherep = RC_REPLY;
        }
        m_freem(nd.nd_mrep);

        if (nd.nd_cred != NULL)
                crfree(nd.nd_cred);

        if (cacherep == RC_DROPIT) {
                m_freem(nd.nd_mreq);
                svc_freereq(rqst);
                goto out;
        }

        if (nd.nd_mreq == NULL) {
                svcerr_decode(rqst);
                svc_freereq(rqst);
                goto out;
        }

        if (nd.nd_repstat & NFSERR_AUTHERR) {
                svcerr_auth(rqst, nd.nd_repstat & ~NFSERR_AUTHERR);
                m_freem(nd.nd_mreq);
        } else if (!svc_sendreply_mbuf(rqst, nd.nd_mreq)) {
                svcerr_systemerr(rqst);
        }
        if (rp != NULL) {
                nfsrvd_sentcache(rp, (rqst->rq_reply_seq != 0 ||
                    SVC_ACK(xprt, NULL)), rqst->rq_reply_seq);
        }
        svc_freereq(rqst);

out:
        if (softdep_ast_cleanup != NULL)
                softdep_ast_cleanup();
        NFSEXITCODE(0);
}

/*
 * Check the cache and, optionally, do the RPC.
 * Return the appropriate cache response.
 */
static int
nfs_proc(struct nfsrv_descript *nd, u_int32_t xid, SVCXPRT *xprt,
    struct nfsrvcache **rpp)
{
        struct thread *td = curthread;
        int cacherep = RC_DOIT, isdgram, taglen = -1;
        struct mbuf *m;
        u_char tag[NFSV4_SMALLSTR + 1], *tagstr = NULL;
        u_int32_t minorvers = 0;
        uint32_t ack;

        *rpp = NULL;
        if (nd->nd_nam2 == NULL) {
                nd->nd_flag |= ND_STREAMSOCK;
                isdgram = 0;
        } else {
                isdgram = 1;
        }

        /*
         * Two cases:
         * 1 - For NFSv2 over UDP, if we are near our malloc/mget
         *     limit, just drop the request. There is no
         *     NFSERR_RESOURCE or NFSERR_DELAY for NFSv2 and the
         *     client will timeout/retry over UDP in a little while.
         * 2 - nd_repstat == 0 && nd_mreq == NULL, which
         *     means a normal nfs rpc, so check the cache
         */
        if ((nd->nd_flag & ND_NFSV2) && nd->nd_nam2 != NULL &&
            nfsrv_mallocmget_limit()) {
                cacherep = RC_DROPIT;
        } else {
                /*
                 * For NFSv3, play it safe and assume that the client is
                 * doing retries on the same TCP connection.
                 */
                if ((nd->nd_flag & (ND_NFSV4 | ND_STREAMSOCK)) ==
                    ND_STREAMSOCK)
                        nd->nd_flag |= ND_SAMETCPCONN;
                nd->nd_retxid = xid;
                nd->nd_tcpconntime = NFSD_MONOSEC;
                nd->nd_sockref = xprt->xp_sockref;
                if ((nd->nd_flag & ND_NFSV4) != 0)
                        nfsd_getminorvers(nd, tag, &tagstr, &taglen,
                            &minorvers);
                if ((nd->nd_flag & ND_NFSV41) != 0)
                        /* NFSv4.1 caches replies in the session slots. */
                        cacherep = RC_DOIT;
                else {
                        cacherep = nfsrvd_getcache(nd);
                        ack = 0;
                        SVC_ACK(xprt, &ack);
                        nfsrc_trimcache(xprt->xp_sockref, ack, 0);
                }
        }

        /*
         * Handle the request. There are three cases.
         * RC_DOIT - do the RPC
         * RC_REPLY - return the reply already created
         * RC_DROPIT - just throw the request away
         */
        if (cacherep == RC_DOIT) {
                if ((nd->nd_flag & ND_NFSV41) != 0)
                        nd->nd_xprt = xprt;
                nfsrvd_dorpc(nd, isdgram, tagstr, taglen, minorvers, td);
                if ((nd->nd_flag & ND_NFSV41) != 0) {
                        if (nd->nd_repstat != NFSERR_REPLYFROMCACHE &&
                            (nd->nd_flag & ND_SAVEREPLY) != 0) {
                                /* Cache a copy of the reply. */
                                m = m_copym(nd->nd_mreq, 0, M_COPYALL,
                                    M_WAITOK);
                        } else
                                m = NULL;
                        if ((nd->nd_flag & ND_HASSEQUENCE) != 0)
                                nfsrv_cache_session(nd->nd_sessionid,
                                    nd->nd_slotid, nd->nd_repstat, &m);
                        if (nd->nd_repstat == NFSERR_REPLYFROMCACHE)
                                nd->nd_repstat = 0;
                        cacherep = RC_REPLY;
                } else {
                        if (nd->nd_repstat == NFSERR_DONTREPLY)
                                cacherep = RC_DROPIT;
                        else
                                cacherep = RC_REPLY;
                        *rpp = nfsrvd_updatecache(nd);
                }
        }
        if (tagstr != NULL && taglen > NFSV4_SMALLSTR)
                free(tagstr, M_TEMP);

        NFSEXITCODE2(0, nd);
        return (cacherep);
}

static void
nfssvc_loss(SVCXPRT *xprt)
{
        uint32_t ack;

        ack = 0;
        SVC_ACK(xprt, &ack);
        nfsrc_trimcache(xprt->xp_sockref, ack, 1);
}

/*
 * Adds a socket to the list for servicing by nfsds.
 */
int
nfsrvd_addsock(struct file *fp)
{
        int siz;
        struct socket *so;
        int error = 0;
        SVCXPRT *xprt;
        static u_int64_t sockref = 0;

        so = fp->f_data;

        siz = sb_max_adj;
        error = soreserve(so, siz, siz);
        if (error)
                goto out;

        /*
         * Steal the socket from userland so that it doesn't close
         * unexpectedly.
         */
        if (so->so_type == SOCK_DGRAM)
                xprt = svc_dg_create(nfsrvd_pool, so, 0, 0);
        else
                xprt = svc_vc_create(nfsrvd_pool, so, 0, 0);
        if (xprt) {
                fp->f_ops = &badfileops;
                fp->f_data = NULL;
                xprt->xp_sockref = ++sockref;
                if (nfs_minvers == NFS_VER2)
                        svc_reg(xprt, NFS_PROG, NFS_VER2, nfssvc_program,
                            NULL);
                if (nfs_minvers <= NFS_VER3 && nfs_maxvers >= NFS_VER3)
                        svc_reg(xprt, NFS_PROG, NFS_VER3, nfssvc_program,
                            NULL);
                if (nfs_maxvers >= NFS_VER4)
                        svc_reg(xprt, NFS_PROG, NFS_VER4, nfssvc_program,
                            NULL);
                if (so->so_type == SOCK_STREAM)
                        svc_loss_reg(xprt, nfssvc_loss);
                SVC_RELEASE(xprt);
        }

out:
        NFSEXITCODE(error);
        return (error);
}

/*
 * Called by nfssvc() for nfsds. Just loops around servicing rpc requests
 * until it is killed by a signal.
 */
int
nfsrvd_nfsd(struct thread *td, struct nfsd_nfsd_args *args)
{
        char principal[MAXHOSTNAMELEN + 5];
        struct proc *p;
        int error = 0;
        bool_t ret2, ret3, ret4;

        error = copyinstr(args->principal, principal, sizeof (principal),
            NULL);
        if (error)
                goto out;

        /*
         * 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 (newnfs_numnfsd == 0) {
                p = td->td_proc;
                PROC_LOCK(p);
                p->p_flag2 |= P2_AST_SU;
                PROC_UNLOCK(p);
                newnfs_numnfsd++;

                NFSD_UNLOCK();

                /* An empty string implies AUTH_SYS only. */
                if (principal[0] != '\0') {
                        ret2 = rpc_gss_set_svc_name_call(principal,
                            "kerberosv5", GSS_C_INDEFINITE, NFS_PROG, NFS_VER2);
                        ret3 = rpc_gss_set_svc_name_call(principal,
                            "kerberosv5", GSS_C_INDEFINITE, NFS_PROG, NFS_VER3);
                        ret4 = rpc_gss_set_svc_name_call(principal,
                            "kerberosv5", GSS_C_INDEFINITE, NFS_PROG, NFS_VER4);

                        if (!ret2 || !ret3 || !ret4)
                                printf("nfsd: can't register svc name\n");
                }

                nfsrvd_pool->sp_minthreads = args->minthreads;
                nfsrvd_pool->sp_maxthreads = args->maxthreads;
                        
                svc_run(nfsrvd_pool);

                if (principal[0] != '\0') {
                        rpc_gss_clear_svc_name_call(NFS_PROG, NFS_VER2);
                        rpc_gss_clear_svc_name_call(NFS_PROG, NFS_VER3);
                        rpc_gss_clear_svc_name_call(NFS_PROG, NFS_VER4);
                }

                NFSD_LOCK();
                newnfs_numnfsd--;
                nfsrvd_init(1);
                PROC_LOCK(p);
                p->p_flag2 &= ~P2_AST_SU;
                PROC_UNLOCK(p);
        }
        NFSD_UNLOCK();

out:
        NFSEXITCODE(error);
        return (error);
}

/*
 * Initialize the data structures for the server.
 * Handshake with any new nfsds starting up to avoid any chance of
 * corruption.
 */
void
nfsrvd_init(int terminating)
{

        NFSD_LOCK_ASSERT();

        if (terminating) {
                nfsd_master_proc = NULL;
                NFSD_UNLOCK();
                nfsrv_freeallbackchannel_xprts();
                svcpool_destroy(nfsrvd_pool);
                nfsrvd_pool = NULL;
                NFSD_LOCK();
        }

        NFSD_UNLOCK();

        nfsrvd_pool = svcpool_create("nfsd", SYSCTL_STATIC_CHILDREN(_vfs_nfsd));
        nfsrvd_pool->sp_rcache = NULL;
        nfsrvd_pool->sp_assign = fhanew_assign;
        nfsrvd_pool->sp_done = fha_nd_complete;

        NFSD_LOCK();
}