SUNRPC: Introduce rpcauth_get_pseudoflavor()

A SECINFO reply may contain flavors whose kernel module is not
yet loaded by the client's kernel.  A new RPC client API, called
rpcauth_get_pseudoflavor(), is introduced to do proper checking
for support of a security flavor.

When this API is invoked, the RPC client now tries to load the
module for each flavor first before performing the "is this
supported?" check.  This means if a module is available on the
client, but has not been loaded yet, it will be loaded and
registered automatically when the SECINFO reply is processed.

The new API can take a full GSS tuple (OID, QoP, and service).
Previously only the OID and service were considered.

nfs_find_best_sec() is updated to verify all flavors requested in a
SECINFO reply, including AUTH_NULL and AUTH_UNIX.  Previously these
two flavors were simply assumed to be supported without consulting
the RPC client.

Note that the replaced version of nfs_find_best_sec() can return
RPC_AUTH_MAXFLAVOR if the server returns a recognized OID but an
unsupported "service" value.  nfs_find_best_sec() now returns
RPC_AUTH_UNIX in this case.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 2 insertions, 3 deletions

diff --git a/include/linux/sunrpc/gss_api.h b/include/linux/sunrpc/gss_api.h
index 98950e5a8877..aba7687ca884 100644
--- a/include/linux/sunrpc/gss_api.h
+++ b/include/linux/sunrpc/gss_api.h
@@ -127,9 +127,8 @@ struct gss_api_ops {
 int gss_mech_register(struct gss_api_mech *);
 void gss_mech_unregister(struct gss_api_mech *);
 
-/* returns a mechanism descriptor given an OID, and increments the mechanism's
- * reference count. */
-struct gss_api_mech * gss_mech_get_by_OID(struct xdr_netobj *);
+/* Given a GSS security tuple, look up a pseudoflavor */
+rpc_authflavor_t gss_mech_info2flavor(struct rpcsec_gss_info *);
 
 /* Returns a reference to a mechanism, given a name like "krb5" etc. */
 struct gss_api_mech *gss_mech_get_by_name(const char *);