linux-kernel - [PATCH 4.4 61/93] svc: Avoid garbage replies when pc_func() returns rpc_drop

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Message-Id: <20161006074733.763927151@linuxfoundation.org>
Date:   Thu,  6 Oct 2016 10:29:31 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Chuck Lever <chuck.lever@...cle.com>,
        Steve Wise <swise@...ngridcomputing.com>,
        Anna Schumaker <Anna.Schumaker@...app.com>
Subject: [PATCH 4.4 61/93] svc: Avoid garbage replies when pc_func() returns rpc_drop_reply

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Chuck Lever <chuck.lever@...cle.com>

commit 0533b13072f4bf35738290d2cf9e299c7bc6c42a upstream.

If an RPC program does not set vs_dispatch and pc_func() returns
rpc_drop_reply, the server sends a reply anyway containing a single
word containing the value RPC_DROP_REPLY (in network byte-order, of
course). This is a nonsense RPC message.

Fixes: 9e701c610923 ("svcrpc: simpler request dropping")
Signed-off-by: Chuck Lever <chuck.lever@...cle.com>
Tested-by: Steve Wise <swise@...ngridcomputing.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@...app.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 net/sunrpc/svc.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1188,7 +1188,8 @@ svc_process_common(struct svc_rqst *rqst
 		*statp = procp->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
 
 		/* Encode reply */
-		if (test_bit(RQ_DROPME, &rqstp->rq_flags)) {
+		if (*statp == rpc_drop_reply ||
+		    test_bit(RQ_DROPME, &rqstp->rq_flags)) {
 			if (procp->pc_release)
 				procp->pc_release(rqstp, NULL, rqstp->rq_resp);
 			goto dropit;