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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Andrew Elble <aweits@rit.edu>,
        "J. Bruce Fields" <bfields@redhat.com>,
        Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH 4.4 41/67] nfsd: check for use of the closed special stateid
Date:   Fri,  2 Feb 2018 17:58:10 +0100
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4.4-stable review patch.  If anyone has any objections, please let me know.

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

From: Andrew Elble <aweits@rit.edu>


[ Upstream commit ae254dac721d44c0bfebe2795df87459e2e88219 ]

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

Signed-off-by: Andrew Elble <aweits@rit.edu>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 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);
@@ -4704,7 +4705,8 @@ 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)) {
@@ -4762,7 +4764,8 @@ 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) {