[added to the 4.1 stable tree] nfsd: check for use of the closed special stateid

[Sasha Levin <Alexander.Levin@xxxxxxxxxxxxx>]

From: Andrew Elble <aweits@xxxxxxx>

This patch has been added to the 4.1 stable tree. If you have any
objections, please let us know.

===============

[ Upstream commit ae254dac721d44c0bfebe2795df87459e2e88219 ]

Prevent the use of the closed (invalid) special stateid by clients.

Signed-off-by: Andrew Elble <aweits@xxxxxxx>
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
---
 fs/nfsd/nfs4state.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 72019f141ebc..322cf41b5257 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -72,6 +72,7 @@ static u64 current_sessionid = 1;
 #define ZERO_STATEID(stateid) (!memcmp((stateid), &zero_stateid, sizeof(stateid_t)))
 #define ONE_STATEID(stateid)  (!memcmp((stateid), &one_stateid, sizeof(stateid_t)))
 #define CURRENT_STATEID(stateid) (!memcmp((stateid), &currentstateid, sizeof(stateid_t)))
+#define CLOSE_STATEID(stateid)  (!memcmp((stateid), &close_stateid, sizeof(stateid_t)))
 
 /* forward declarations */
 static bool check_for_locks(struct nfs4_file *fp, struct nfs4_lockowner *lowner);
@@ -4618,7 +4619,8 @@ static __be32 nfsd4_validate_stateid(struct nfs4_client *cl, stateid_t *stateid)
 	struct nfs4_stid *s;
 	__be32 status = nfserr_bad_stateid;
 
-	if (ZERO_STATEID(stateid) || ONE_STATEID(stateid))
+	if (ZERO_STATEID(stateid) || ONE_STATEID(stateid) ||
+		CLOSE_STATEID(stateid))
 		return status;
 	/* Client debugging aid. */
 	if (!same_clid(&stateid->si_opaque.so_clid, &cl->cl_clientid)) {
@@ -4676,7 +4678,8 @@ nfsd4_lookup_stateid(struct nfsd4_compound_state *cstate,
 	else if (typemask & NFS4_DELEG_STID)
 		typemask |= NFS4_REVOKED_DELEG_STID;
 
-	if (ZERO_STATEID(stateid) || ONE_STATEID(stateid))
+	if (ZERO_STATEID(stateid) || ONE_STATEID(stateid) ||
+		CLOSE_STATEID(stateid))
 		return nfserr_bad_stateid;
 	status = lookup_clientid(&stateid->si_opaque.so_clid, cstate, nn);
 	if (status == nfserr_stale_clientid) {
-- 
2.14.1