[PATCH 2/2] nfsd4: setclientid_confirm with unmatched verifier should fail

["J. Bruce Fields" <bfields@redhat.com>]

From: "J. Bruce Fields" <bfields@redhat.com>

A setclientid_confirm with (clientid, verifier) both matching an
existing confirmed record is assumed to be a replay, but if the verifier
doesn't match, it shouldn't be.

This would be a very rare case, except that clients following
https://tools.ietf.org/html/rfc7931#section-5.8 may depend on the
failure.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
---
 fs/nfsd/nfs4state.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index a204d7e109d4..4b657337cbcd 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -3224,9 +3224,10 @@ nfsd4_setclientid_confirm(struct svc_rqst *rqstp,
 		goto out;
 	/* cases below refer to rfc 3530 section 14.2.34: */
 	if (!unconf || !same_verf(&confirm, &unconf->cl_confirm)) {
-		if (conf && !unconf) /* case 2: probable retransmit */
+		if (conf && same_verf(&confirm, &conf->cl_confirm)) {
+			/* case 2: probable retransmit */
 			status = nfs_ok;
-		else /* case 4: client hasn't noticed we rebooted yet? */
+		} else /* case 4: client hasn't noticed we rebooted yet? */
 			status = nfserr_stale_clientid;
 		goto out;
 	}
-- 
2.7.4