lockd: Introduce new-style XDR functions for NLMv4

We'd like to prevent local buffer overflows caused by malicious or
broken servers.  New xdr_stream style decoders can do that.

For efficiency, we also want to be able to pass xdr_streams from
call_encode() to all XDR encoding functions, rather than building
an xdr_stream in every XDR encoding function in the kernel.

Same idea as the NLM v3 XDR overhaul.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/lockd/Makefile

@@ -6,5 +6,5 @@ obj-$(CONFIG_LOCKD) += lockd.o
 
 lockd-objs-y := clntlock.o clntproc.o clntxdr.o host.o svc.o svclock.o \
 	        svcshare.o svcproc.o svcsubs.o mon.o xdr.o grace.o
-lockd-objs-$(CONFIG_LOCKD_V4) += xdr4.o svc4proc.o
+lockd-objs-$(CONFIG_LOCKD_V4) += clnt4xdr.o xdr4.o svc4proc.o
 lockd-objs		      := $(lockd-objs-y)

fs/lockd/xdr4.c

@@ -93,15 +93,6 @@ nlm4_decode_fh(__be32 *p, struct nfs_fh *f)
 	return p + XDR_QUADLEN(f->size);
 }
 
-static __be32 *
-nlm4_encode_fh(__be32 *p, struct nfs_fh *f)
-{
-	*p++ = htonl(f->size);
-	if (f->size) p[XDR_QUADLEN(f->size)-1] = 0; /* don't leak anything */
-	memcpy(p, f->data, f->size);
-	return p + XDR_QUADLEN(f->size);
-}
-
 /*
  * Encode and decode owner handle
  */
@@ -111,12 +102,6 @@ nlm4_decode_oh(__be32 *p, struct xdr_netobj *oh)
 	return xdr_decode_netobj(p, oh);
 }
 
-static __be32 *
-nlm4_encode_oh(__be32 *p, struct xdr_netobj *oh)
-{
-	return xdr_encode_netobj(p, oh);
-}
-
 static __be32 *
 nlm4_decode_lock(__be32 *p, struct nlm_lock *lock)
 {
@@ -149,38 +134,6 @@ nlm4_decode_lock(__be32 *p, struct nlm_lock *lock)
 	return p;
 }
 
-/*
- * Encode a lock as part of an NLM call
- */
-static __be32 *
-nlm4_encode_lock(__be32 *p, struct nlm_lock *lock)
-{
-	struct file_lock	*fl = &lock->fl;
-	__s64			start, len;
-
-	if (!(p = xdr_encode_string(p, lock->caller))
-	 || !(p = nlm4_encode_fh(p, &lock->fh))
-	 || !(p = nlm4_encode_oh(p, &lock->oh)))
-		return NULL;
-
-	if (fl->fl_start > NLM4_OFFSET_MAX
-	 || (fl->fl_end > NLM4_OFFSET_MAX && fl->fl_end != OFFSET_MAX))
-		return NULL;
-
-	*p++ = htonl(lock->svid);
-
-	start = loff_t_to_s64(fl->fl_start);
-	if (fl->fl_end == OFFSET_MAX)
-		len = 0;
-	else
-		len = loff_t_to_s64(fl->fl_end - fl->fl_start + 1);
-
-	p = xdr_encode_hyper(p, start);
-	p = xdr_encode_hyper(p, len);
-
-	return p;
-}
-
 /*
  * Encode result of a TEST/TEST_MSG call
  */
@@ -379,211 +332,3 @@ nlm4svc_encode_void(struct svc_rqst *rqstp, __be32 *p, void *dummy)
 {
 	return xdr_ressize_check(rqstp, p);
 }
-
-/*
- * Now, the client side XDR functions
- */
-#ifdef NLMCLNT_SUPPORT_SHARES
-static int
-nlm4clt_decode_void(struct rpc_rqst *req, __be32 *p, void *ptr)
-{
-	return 0;
-}
-#endif
-
-static int
-nlm4clt_encode_testargs(struct rpc_rqst *req, __be32 *p, nlm_args *argp)
-{
-	struct nlm_lock	*lock = &argp->lock;
-
-	if (!(p = nlm4_encode_cookie(p, &argp->cookie)))
-		return -EIO;
-	*p++ = (lock->fl.fl_type == F_WRLCK)? xdr_one : xdr_zero;
-	if (!(p = nlm4_encode_lock(p, lock)))
-		return -EIO;
-	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
-	return 0;
-}
-
-static int
-nlm4clt_decode_testres(struct rpc_rqst *req, __be32 *p, struct nlm_res *resp)
-{
-	if (!(p = nlm4_decode_cookie(p, &resp->cookie)))
-		return -EIO;
-	resp->status = *p++;
-	if (resp->status == nlm_lck_denied) {
-		struct file_lock	*fl = &resp->lock.fl;
-		u32			excl;
-		__u64			start, len;
-		__s64			end;
-
-		memset(&resp->lock, 0, sizeof(resp->lock));
-		locks_init_lock(fl);
-		excl = ntohl(*p++);
-		resp->lock.svid = ntohl(*p++);
-		fl->fl_pid = (pid_t)resp->lock.svid;
-		if (!(p = nlm4_decode_oh(p, &resp->lock.oh)))
-			return -EIO;
-
-		fl->fl_flags = FL_POSIX;
-		fl->fl_type  = excl? F_WRLCK : F_RDLCK;
-		p = xdr_decode_hyper(p, &start);
-		p = xdr_decode_hyper(p, &len);
-		end = start + len - 1;
-
-		fl->fl_start = s64_to_loff_t(start);
-		if (len == 0 || end < 0)
-			fl->fl_end = OFFSET_MAX;
-		else
-			fl->fl_end = s64_to_loff_t(end);
-	}
-	return 0;
-}
-
-
-static int
-nlm4clt_encode_lockargs(struct rpc_rqst *req, __be32 *p, nlm_args *argp)
-{
-	struct nlm_lock	*lock = &argp->lock;
-
-	if (!(p = nlm4_encode_cookie(p, &argp->cookie)))
-		return -EIO;
-	*p++ = argp->block? xdr_one : xdr_zero;
-	*p++ = (lock->fl.fl_type == F_WRLCK)? xdr_one : xdr_zero;
-	if (!(p = nlm4_encode_lock(p, lock)))
-		return -EIO;
-	*p++ = argp->reclaim? xdr_one : xdr_zero;
-	*p++ = htonl(argp->state);
-	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
-	return 0;
-}
-
-static int
-nlm4clt_encode_cancargs(struct rpc_rqst *req, __be32 *p, nlm_args *argp)
-{
-	struct nlm_lock	*lock = &argp->lock;
-
-	if (!(p = nlm4_encode_cookie(p, &argp->cookie)))
-		return -EIO;
-	*p++ = argp->block? xdr_one : xdr_zero;
-	*p++ = (lock->fl.fl_type == F_WRLCK)? xdr_one : xdr_zero;
-	if (!(p = nlm4_encode_lock(p, lock)))
-		return -EIO;
-	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
-	return 0;
-}
-
-static int
-nlm4clt_encode_unlockargs(struct rpc_rqst *req, __be32 *p, nlm_args *argp)
-{
-	struct nlm_lock	*lock = &argp->lock;
-
-	if (!(p = nlm4_encode_cookie(p, &argp->cookie)))
-		return -EIO;
-	if (!(p = nlm4_encode_lock(p, lock)))
-		return -EIO;
-	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
-	return 0;
-}
-
-static int
-nlm4clt_encode_res(struct rpc_rqst *req, __be32 *p, struct nlm_res *resp)
-{
-	if (!(p = nlm4_encode_cookie(p, &resp->cookie)))
-		return -EIO;
-	*p++ = resp->status;
-	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
-	return 0;
-}
-
-static int
-nlm4clt_encode_testres(struct rpc_rqst *req, __be32 *p, struct nlm_res *resp)
-{
-	if (!(p = nlm4_encode_testres(p, resp)))
-		return -EIO;
-	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
-	return 0;
-}
-
-static int
-nlm4clt_decode_res(struct rpc_rqst *req, __be32 *p, struct nlm_res *resp)
-{
-	if (!(p = nlm4_decode_cookie(p, &resp->cookie)))
-		return -EIO;
-	resp->status = *p++;
-	return 0;
-}
-
-#if (NLMCLNT_OHSIZE > XDR_MAX_NETOBJ)
-#  error "NLM host name cannot be larger than XDR_MAX_NETOBJ!"
-#endif
-
-#if (NLMCLNT_OHSIZE > NLM_MAXSTRLEN)
-#  error "NLM host name cannot be larger than NLM's maximum string length!"
-#endif
-
-/*
- * Buffer requirements for NLM
- */
-#define NLM4_void_sz		0
-#define NLM4_cookie_sz		1+XDR_QUADLEN(NLM_MAXCOOKIELEN)
-#define NLM4_caller_sz		1+XDR_QUADLEN(NLMCLNT_OHSIZE)
-#define NLM4_owner_sz		1+XDR_QUADLEN(NLMCLNT_OHSIZE)
-#define NLM4_fhandle_sz		1+XDR_QUADLEN(NFS3_FHSIZE)
-#define NLM4_lock_sz		5+NLM4_caller_sz+NLM4_owner_sz+NLM4_fhandle_sz
-#define NLM4_holder_sz		6+NLM4_owner_sz
-
-#define NLM4_testargs_sz	NLM4_cookie_sz+1+NLM4_lock_sz
-#define NLM4_lockargs_sz	NLM4_cookie_sz+4+NLM4_lock_sz
-#define NLM4_cancargs_sz	NLM4_cookie_sz+2+NLM4_lock_sz
-#define NLM4_unlockargs_sz	NLM4_cookie_sz+NLM4_lock_sz
-
-#define NLM4_testres_sz		NLM4_cookie_sz+1+NLM4_holder_sz
-#define NLM4_res_sz		NLM4_cookie_sz+1
-#define NLM4_norep_sz		0
-
-/*
- * For NLM, a void procedure really returns nothing
- */
-#define nlm4clt_decode_norep	NULL
-
-#define PROC(proc, argtype, restype)					\
-[NLMPROC_##proc] = {							\
-	.p_proc      = NLMPROC_##proc,					\
-	.p_encode    = (kxdrproc_t) nlm4clt_encode_##argtype,		\
-	.p_decode    = (kxdrproc_t) nlm4clt_decode_##restype,		\
-	.p_arglen    = NLM4_##argtype##_sz,				\
-	.p_replen    = NLM4_##restype##_sz,				\
-	.p_statidx   = NLMPROC_##proc,					\
-	.p_name      = #proc,						\
-	}
-
-static struct rpc_procinfo	nlm4_procedures[] = {
-    PROC(TEST,		testargs,	testres),
-    PROC(LOCK,		lockargs,	res),
-    PROC(CANCEL,	cancargs,	res),
-    PROC(UNLOCK,	unlockargs,	res),
-    PROC(GRANTED,	testargs,	res),
-    PROC(TEST_MSG,	testargs,	norep),
-    PROC(LOCK_MSG,	lockargs,	norep),
-    PROC(CANCEL_MSG,	cancargs,	norep),
-    PROC(UNLOCK_MSG,	unlockargs,	norep),
-    PROC(GRANTED_MSG,	testargs,	norep),
-    PROC(TEST_RES,	testres,	norep),
-    PROC(LOCK_RES,	res,		norep),
-    PROC(CANCEL_RES,	res,		norep),
-    PROC(UNLOCK_RES,	res,		norep),
-    PROC(GRANTED_RES,	res,		norep),
-#ifdef NLMCLNT_SUPPORT_SHARES
-    PROC(SHARE,		shareargs,	shareres),
-    PROC(UNSHARE,	shareargs,	shareres),
-    PROC(NM_LOCK,	lockargs,	res),
-    PROC(FREE_ALL,	notify,		void),
-#endif
-};
-
-struct rpc_version	nlm_version4 = {
-	.number		= 4,
-	.nrprocs	= 24,
-	.procs		= nlm4_procedures,
-};