nfsd4: allow client to send no cb_sec flavors

In testing I notice that some of the pynfs tests forget to send any
cb_sec flavors, and that we haven't necessarily errored out in that case
before.

I'll fix pynfs, but am also inclined to default to trying AUTH_NONE in
that case in case this is something clients actually do.

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

1 files changed, 5 insertions, 1 deletions

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 3126210383bd..171fe5e4af67 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -460,7 +460,11 @@ static __be32 nfsd4_decode_cb_sec(struct nfsd4_compoundargs *argp, struct nfsd4_
         /* callback_sec_params4 */
         READ_BUF(4);
         READ32(nr_secflavs);
-        cbs->flavor = (u32)(-1);
+        if (nr_secflavs)
+                cbs->flavor = (u32)(-1);
+        else
+                /* Is this legal? Be generous, take it to mean AUTH_NONE: */
+                cbs->flavor = 0;
         for (i = 0; i < nr_secflavs; ++i) {
                 READ_BUF(4);
                 READ32(dummy);