NFS: Don't drop CB requests with invalid principals

Before commit 778be232a207 ("NFS do not find client in NFSv4
pg_authenticate"), the Linux callback server replied with
RPC_AUTH_ERROR / RPC_AUTH_BADCRED, instead of dropping the CB
request. Let's restore that behavior so the server has a chance to
do something useful about it, and provide a warning that helps
admins correct the problem.

Fixes: 778be232a207 ("NFS do not find client in NFSv4 ...")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

2 files changed, 10 insertions, 1 deletions

diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
index d81f96aacd51..656f68f7fe53 100644
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -925,7 +925,7 @@ static __be32 nfs4_callback_compound(struct svc_rqst *rqstp, void *argp, void *r
         if (hdr_arg.minorversion == 0) {
                 cps.clp = nfs4_find_client_ident(SVC_NET(rqstp), hdr_arg.cb_ident);
                 if (!cps.clp || !check_gss_callback_principal(cps.clp, rqstp))
-                        return rpc_drop_reply;
+                        goto out_invalidcred;
         }
 
         cps.minorversion = hdr_arg.minorversion;
@@ -953,6 +953,10 @@ static __be32 nfs4_callback_compound(struct svc_rqst *rqstp, void *argp, void *r
         nfs_put_client(cps.clp);
         dprintk("%s: done, status = %u\n", __func__, ntohl(status));
         return rpc_success;
+
+out_invalidcred:
+        pr_warn_ratelimited("NFS: NFSv4 callback contains invalid cred\n");
+        return rpc_autherr_badcred;
 }
 
 /*
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 87290a5a9ac7..c5b0cb4f4056 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1194,6 +1194,11 @@ svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
                                 procp->pc_release(rqstp, NULL, rqstp->rq_resp);
                         goto dropit;
                 }
+                if (*statp == rpc_autherr_badcred) {
+                        if (procp->pc_release)
+                                procp->pc_release(rqstp, NULL, rqstp->rq_resp);
+                        goto err_bad_auth;
+                }
                 if (*statp == rpc_success &&
                     (xdr = procp->pc_encode) &&
                     !xdr(rqstp, resv->iov_base+resv->iov_len, rqstp->rq_resp)) {