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Commit 511d2e88 authored by Chuck Lever's avatar Chuck Lever Committed by Trond Myklebust
Browse files

NLM: Shrink the maximum request size of NLM4 requests 



NLM version 4 requests estimate the call and reply header sizes rather
conservatively, using the very maximum size allowed in the protocol even
though Linux always uses only a small fraction of the allowable space.

Reduce the size of caller and lock arguments to conserve RPC buffer space
while XDR encoding NLM4 arguments.  Add compile-time checks to ensure the
hostname string won't overflow NLM protocol maximums.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent ca52fec1

fs/lockd/xdr.c

+8 −5
Original line number Diff line number Diff line
@@ -510,17 +510,20 @@ nlmclt_decode_res(struct rpc_rqst *req, __be32 *p, struct nlm_res *resp) 
	return 0;

}



#if (NLMCLNT_OHSIZE > XDR_MAX_NETOBJ)

#  error "NLM host name cannot be larger than XDR_MAX_NETOBJ!"

#endif



/*

 * Buffer requirements for NLM

 */

#define NLM_void_sz		0

#define NLM_cookie_sz		1+XDR_QUADLEN(NLM_MAXCOOKIELEN)

#define NLM_caller_sz		1+XDR_QUADLEN(sizeof(utsname()->nodename))

#define NLM_netobj_sz		1+XDR_QUADLEN(XDR_MAX_NETOBJ)

/* #define NLM_owner_sz		1+XDR_QUADLEN(NLM_MAXOWNER) */

#define NLM_caller_sz		1+XDR_QUADLEN(NLMCLNT_OHSIZE)

#define NLM_owner_sz		1+XDR_QUADLEN(NLMCLNT_OHSIZE)

#define NLM_fhandle_sz		1+XDR_QUADLEN(NFS2_FHSIZE)

#define NLM_lock_sz		3+NLM_caller_sz+NLM_netobj_sz+NLM_fhandle_sz

#define NLM_holder_sz		4+NLM_netobj_sz

#define NLM_lock_sz		3+NLM_caller_sz+NLM_owner_sz+NLM_fhandle_sz

#define NLM_holder_sz		4+NLM_owner_sz



#define NLM_testargs_sz		NLM_cookie_sz+1+NLM_lock_sz

#define NLM_lockargs_sz		NLM_cookie_sz+4+NLM_lock_sz

fs/lockd/xdr4.c

+12 −5
Original line number Diff line number Diff line
@@ -516,17 +516,24 @@ nlm4clt_decode_res(struct rpc_rqst *req, __be32 *p, struct nlm_res *resp) 
	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(NLM_MAXSTRLEN)

#define NLM4_netobj_sz		1+XDR_QUADLEN(XDR_MAX_NETOBJ)

/* #define NLM4_owner_sz		1+XDR_QUADLEN(NLM4_MAXOWNER) */

#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_netobj_sz+NLM4_fhandle_sz

#define NLM4_holder_sz		6+NLM4_netobj_sz

#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

include/linux/lockd/lockd.h

+1 −1
Original line number Diff line number Diff line
@@ -88,7 +88,7 @@ struct nlm_wait; 
/*

 * Memory chunk for NLM client RPC request.

 */

#define NLMCLNT_OHSIZE		(sizeof(utsname()->nodename)+10)

#define NLMCLNT_OHSIZE		((__NEW_UTS_LEN) + 10u)

struct nlm_rqst {

	unsigned int		a_flags;	/* initial RPC task flags */

	struct nlm_host *	a_host;		/* host handle */