[PATCH 13/23] SUNRPC: introduce RPC_TASK_NULLCREDS to request auth_none

From: NeilBrown
Date: Sun Dec 02 2018 - 19:33:25 EST


In almost all cases the credential stored in rpc_message.rpc_cred
is a "generic" credential. One of the two expections is when an
AUTH_NULL credential is used such as for RPC ping requests.

To improve consistency, don't pass an explicit credential in
these cases, but instead pass NULL and set a task flag,
similar to RPC_TASK_ROOTCREDS, which requests that NULL credentials
be used by default.

Signed-off-by: NeilBrown <neilb@xxxxxxxx>
---
include/linux/sunrpc/sched.h | 1 +
net/sunrpc/auth.c | 2 ++
net/sunrpc/clnt.c | 19 ++++++-------------
3 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h
index f542dad8d4ab..bd722ebc70b7 100644
--- a/include/linux/sunrpc/sched.h
+++ b/include/linux/sunrpc/sched.h
@@ -118,6 +118,7 @@ struct rpc_task_setup {
*/
#define RPC_TASK_ASYNC 0x0001 /* is an async task */
#define RPC_TASK_SWAPPER 0x0002 /* is swapping in/out */
+#define RPC_TASK_NULLCREDS 0x0010 /* Use AUTH_NULL credential */
#define RPC_CALL_MAJORSEEN 0x0020 /* major timeout seen */
#define RPC_TASK_ROOTCREDS 0x0040 /* force root creds */
#define RPC_TASK_DYNAMIC 0x0080 /* task was kmalloc'ed */
diff --git a/net/sunrpc/auth.c b/net/sunrpc/auth.c
index 9e709dcc8c39..dcfcc590b34e 100644
--- a/net/sunrpc/auth.c
+++ b/net/sunrpc/auth.c
@@ -761,6 +761,8 @@ rpcauth_bindcred(struct rpc_task *task, struct rpc_cred *cred, int flags)
;
else if (cred == &machine_cred || (flags & RPC_TASK_ROOTCREDS))
new = rpcauth_bind_root_cred(task, lookupflags);
+ else if (flags & RPC_TASK_NULLCREDS)
+ new = authnull_ops.lookup_cred(NULL, NULL, 0);
else
new = rpcauth_bind_new_cred(task, lookupflags);
if (IS_ERR(new))
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 7c720b60f482..1217d874202c 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -2513,9 +2513,8 @@ static int rpc_ping(struct rpc_clnt *clnt)
.rpc_proc = &rpcproc_null,
};
int err;
- msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
- err = rpc_call_sync(clnt, &msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN);
- put_rpccred(msg.rpc_cred);
+ err = rpc_call_sync(clnt, &msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN |
+ RPC_TASK_NULLCREDS);
return err;
}

@@ -2585,7 +2584,6 @@ int rpc_clnt_test_and_add_xprt(struct rpc_clnt *clnt,
void *dummy)
{
struct rpc_cb_add_xprt_calldata *data;
- struct rpc_cred *cred;
struct rpc_task *task;

data = kmalloc(sizeof(*data), GFP_NOFS);
@@ -2594,11 +2592,9 @@ int rpc_clnt_test_and_add_xprt(struct rpc_clnt *clnt,
data->xps = xprt_switch_get(xps);
data->xprt = xprt_get(xprt);

- cred = authnull_ops.lookup_cred(NULL, NULL, 0);
- task = rpc_call_null_helper(clnt, xprt, cred,
- RPC_TASK_SOFT|RPC_TASK_SOFTCONN|RPC_TASK_ASYNC,
+ task = rpc_call_null_helper(clnt, xprt, NULL,
+ RPC_TASK_SOFT|RPC_TASK_SOFTCONN|RPC_TASK_ASYNC|RPC_TASK_NULLCREDS,
&rpc_cb_add_xprt_call_ops, data);
- put_rpccred(cred);
if (IS_ERR(task))
return PTR_ERR(task);
rpc_put_task(task);
@@ -2629,7 +2625,6 @@ int rpc_clnt_setup_test_and_add_xprt(struct rpc_clnt *clnt,
struct rpc_xprt *xprt,
void *data)
{
- struct rpc_cred *cred;
struct rpc_task *task;
struct rpc_add_xprt_test *xtest = (struct rpc_add_xprt_test *)data;
int status = -EADDRINUSE;
@@ -2641,11 +2636,9 @@ int rpc_clnt_setup_test_and_add_xprt(struct rpc_clnt *clnt,
goto out_err;

/* Test the connection */
- cred = authnull_ops.lookup_cred(NULL, NULL, 0);
- task = rpc_call_null_helper(clnt, xprt, cred,
- RPC_TASK_SOFT | RPC_TASK_SOFTCONN,
+ task = rpc_call_null_helper(clnt, xprt, NULL,
+ RPC_TASK_SOFT | RPC_TASK_SOFTCONN | RPC_TASK_NULLCREDS,
NULL, NULL);
- put_rpccred(cred);
if (IS_ERR(task)) {
status = PTR_ERR(task);
goto out_err;