[PATCH 4.9 44/86] nfsd: check for use of the closed special stateid

[Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Andrew Elble <aweits@xxxxxxx>


[ 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>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 fs/nfsd/nfs4state.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

--- 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);
@@ -4869,7 +4870,8 @@ static __be32 nfsd4_validate_stateid(str
 	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)) {
@@ -4927,7 +4929,8 @@ nfsd4_lookup_stateid(struct nfsd4_compou
 	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) {