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>
diff --git a/net/sunrpc/auth.c b/net/sunrpc/auth.c
index f529404..9b81be8 100644
--- a/net/sunrpc/auth.c
+++ b/net/sunrpc/auth.c
@@ -124,6 +124,41 @@
EXPORT_SYMBOL_GPL(rpcauth_unregister);
/**
+ * rpcauth_get_pseudoflavor - check if security flavor is supported
+ * @flavor: a security flavor
+ * @info: a GSS mech OID, quality of protection, and service value
+ *
+ * Verifies that an appropriate kernel module is available or already loaded.
+ * Returns an equivalent pseudoflavor, or RPC_AUTH_MAXFLAVOR if "flavor" is
+ * not supported locally.
+ */
+rpc_authflavor_t
+rpcauth_get_pseudoflavor(rpc_authflavor_t flavor, struct rpcsec_gss_info *info)
+{
+ const struct rpc_authops *ops;
+ rpc_authflavor_t pseudoflavor;
+
+ ops = auth_flavors[flavor];
+ if (ops == NULL)
+ request_module("rpc-auth-%u", flavor);
+ spin_lock(&rpc_authflavor_lock);
+ ops = auth_flavors[flavor];
+ if (ops == NULL || !try_module_get(ops->owner)) {
+ spin_unlock(&rpc_authflavor_lock);
+ return RPC_AUTH_MAXFLAVOR;
+ }
+ spin_unlock(&rpc_authflavor_lock);
+
+ pseudoflavor = flavor;
+ if (ops->info2flavor != NULL)
+ pseudoflavor = ops->info2flavor(info);
+
+ module_put(ops->owner);
+ return pseudoflavor;
+}
+EXPORT_SYMBOL_GPL(rpcauth_get_pseudoflavor);
+
+/**
* rpcauth_list_flavors - discover registered flavors and pseudoflavors
* @array: array to fill in
* @size: size of "array"