nfsd: fix clid_inuse on mount with security change

In bakeathon testing Solaris client was getting CLID_INUSE error when
doing a krb5 mount soon after an auth_sys mount, or vice versa.

That's not really necessary since in this case the old client doesn't
have any state any more:

	http://tools.ietf.org/html/rfc7530#page-103

	"when the server gets a SETCLIENTID for a client ID that
	currently has no state, or it has state but the lease has
	expired, rather than returning NFS4ERR_CLID_INUSE, the server
	MUST allow the SETCLIENTID and confirm the new client ID if
	followed by the appropriate SETCLIENTID_CONFIRM."

This doesn't fix the problem completely since our client_has_state()
check counts openowners left around to handle close replays, which we
should probably just remove in this case.

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

1 files changed, 8 insertions, 2 deletions

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 1b39edf10b67..bac6207191d5 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -2262,7 +2262,8 @@ static bool client_has_state(struct nfs4_client *clp)
          * Note clp->cl_openowners check isn't quite right: there's no
          * need to count owners without stateid's.
          *
-         * Also note we should probably be using this in 4.0 case too.
+         * Also note in 4.0 case should also be checking for openowners
+         * kept around just for close handling.
          */
         return !list_empty(&clp->cl_openowners)
 #ifdef CONFIG_NFSD_PNFS
@@ -3049,7 +3050,7 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
         /* Cases below refer to rfc 3530 section 14.2.33: */
         spin_lock(&nn->client_lock);
         conf = find_confirmed_client_by_name(&clname, nn);
-        if (conf) {
+        if (conf && client_has_state(conf)) {
                 /* case 0: */
                 status = nfserr_clid_inuse;
                 if (clp_used_exchangeid(conf))
@@ -3136,6 +3137,11 @@ nfsd4_setclientid_confirm(struct svc_rqst *rqstp,
         } else { /* case 3: normal case; new or rebooted client */
                 old = find_confirmed_client_by_name(&unconf->cl_name, nn);
                 if (old) {
+                        status = nfserr_clid_inuse;
+                        if (client_has_state(old)
+                                        && !same_creds(&unconf->cl_cred,
+                                                        &old->cl_cred))
+                                goto out;
                         status = mark_client_expired_locked(old);
                         if (status) {
                                 old = NULL;