SUNRPC: Fail quickly when server does not recognize TLS

rpcauth_checkverf() should return a distinct error code when a
server recognizes the AUTH_TLS probe but does not support TLS so
that the client's header decoder can respond appropriately and
quickly. No retries are necessary is in this case, since the server
has already affirmatively answered "TLS is unsupported".

Suggested-by: Trond Myklebust <trondmy@hammerspace.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

diff --git a/net/sunrpc/auth.c b/net/sunrpc/auth.c
index 2f16f9d..814b016 100644 (file)
--- a/net/sunrpc/auth.c
+++ b/net/sunrpc/auth.c
@@ -769,9 +769,14 @@ int rpcauth_wrap_req(struct rpc_task *task, struct xdr_stream *xdr)
  * @task: controlling RPC task
  * @xdr: xdr_stream containing RPC Reply header
  *
- * On success, @xdr is updated to point past the verifier and
- * zero is returned. Otherwise, @xdr is in an undefined state
- * and a negative errno is returned.
+ * Return values:
+ *   %0: Verifier is valid. @xdr now points past the verifier.
+ *   %-EIO: Verifier is corrupted or message ended early.
+ *   %-EACCES: Verifier is intact but not valid.
+ *   %-EPROTONOSUPPORT: Server does not support the requested auth type.
+ *
+ * When a negative errno is returned, @xdr is left in an undefined
+ * state.
  */
 int
 rpcauth_checkverf(struct rpc_task *task, struct xdr_stream *xdr)

diff --git a/net/sunrpc/auth_tls.c b/net/sunrpc/auth_tls.c
index de7678f..87f570f 100644 (file)
--- a/net/sunrpc/auth_tls.c
+++ b/net/sunrpc/auth_tls.c
@@ -129,9 +129,9 @@ static int tls_validate(struct rpc_task *task, struct xdr_stream *xdr)
        if (*p != rpc_auth_null)
                return -EIO;
        if (xdr_stream_decode_opaque_inline(xdr, &str, starttls_len) != starttls_len)
-               return -EIO;
+               return -EPROTONOSUPPORT;
        if (memcmp(str, starttls_token, starttls_len))
-               return -EIO;
+               return -EPROTONOSUPPORT;
        return 0;
 }
 

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 37b0b21..ea12ed3 100644 (file)
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -2725,7 +2725,15 @@ out_unparsable:
 
 out_verifier:
        trace_rpc_bad_verifier(task);
-       goto out_garbage;
+       switch (error) {
+       case -EPROTONOSUPPORT:
+               goto out_err;
+       case -EACCES:
+               /* Re-encode with a fresh cred */
+               fallthrough;
+       default:
+               goto out_garbage;
+       }
 
 out_msg_denied:
        error = -EACCES;