nfsd4: exchange_id: check creds before killing confirmed client

We mustn't allow a client to destroy another client with established
state unless it has the right credential.

And some minor cleanup.

(Note: our comparison of credentials is actually pretty bogus currently;
that will need to be fixed in another patch.)

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 8 insertions, 9 deletions

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index aca84c942595..f372a6edef34 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1556,6 +1556,14 @@ nfsd4_exchange_id(struct svc_rqst *rqstp,
                         status = nfserr_clid_inuse; /* XXX: ? */
                         goto out;
                 }
+                if (!same_creds(&conf->cl_cred, &rqstp->rq_cred)) {
+                        /* 18.35.4 case 9 */
+                        if (exid->flags & EXCHGID4_FLAG_UPD_CONFIRMED_REC_A)
+                                status = nfserr_perm;
+                        else /* case 3 */
+                                status = nfserr_clid_inuse;
+                        goto out;
+                }
                 if (!same_verf(&verf, &conf->cl_verifier)) {
                         /* 18.35.4 case 8 */
                         if (exid->flags & EXCHGID4_FLAG_UPD_CONFIRMED_REC_A) {
@@ -1566,15 +1574,6 @@ nfsd4_exchange_id(struct svc_rqst *rqstp,
                         expire_client(conf);
                         goto out_new;
                 }
-                if (!same_creds(&conf->cl_cred, &rqstp->rq_cred)) {
-                        /* 18.35.4 case 9 */
-                        if (exid->flags & EXCHGID4_FLAG_UPD_CONFIRMED_REC_A) {
-                                status = nfserr_perm;
-                                goto out;
-                        }
-                        expire_client(conf);
-                        goto out_new;
-                }
                 /*
                  * Set bit when the owner id and verifier map to an already
                  * confirmed client id (18.35.3).