* Copyright (c) 1989, 1993

/* $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();
}