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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Trond Myklebust <trondmy@gmail.com>,
	Trond Myklebust <trond.myklebust@hammerspace.com>,
	Anna Schumaker <Anna.Schumaker@Netapp.com>,
	Sasha Levin <sashal@kernel.org>,
	linux-nfs@vger.kernel.org, netdev@vger.kernel.org
Subject: [PATCH AUTOSEL 5.2 21/63] SUNRPC: Don't try to parse incomplete RPC messages
Date: Tue,  1 Oct 2019 12:40:43 -0400
Message-ID: <20191001164125.15398-21-sashal@kernel.org> (raw)
In-Reply-To: <20191001164125.15398-1-sashal@kernel.org>

From: Trond Myklebust <trondmy@gmail.com>

[ Upstream commit 9ba828861c56a21d211d5d10f5643774b1ea330d ]

If the copy of the RPC reply into our buffers did not complete, and
we could end up with a truncated message. In that case, just resend
the call.

Fixes: a0584ee9aed80 ("SUNRPC: Use struct xdr_stream when decoding...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/sunrpc/clnt.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 8f32f73614111..866b60313fb12 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -2398,6 +2398,7 @@ call_decode(struct rpc_task *task)
 	struct rpc_clnt	*clnt = task->tk_client;
 	struct rpc_rqst	*req = task->tk_rqstp;
 	struct xdr_stream xdr;
+	int err;
 
 	dprint_status(task);
 
@@ -2420,6 +2421,15 @@ call_decode(struct rpc_task *task)
 	 * before it changed req->rq_reply_bytes_recvd.
 	 */
 	smp_rmb();
+
+	/*
+	 * Did we ever call xprt_complete_rqst()? If not, we should assume
+	 * the message is incomplete.
+	 */
+	err = -EAGAIN;
+	if (!req->rq_reply_bytes_recvd)
+		goto out;
+
 	req->rq_rcv_buf.len = req->rq_private_buf.len;
 
 	/* Check that the softirq receive buffer is valid */
@@ -2428,7 +2438,9 @@ call_decode(struct rpc_task *task)
 
 	xdr_init_decode(&xdr, &req->rq_rcv_buf,
 			req->rq_rcv_buf.head[0].iov_base, req);
-	switch (rpc_decode_header(task, &xdr)) {
+	err = rpc_decode_header(task, &xdr);
+out:
+	switch (err) {
 	case 0:
 		task->tk_action = rpc_exit_task;
 		task->tk_status = rpcauth_unwrap_resp(task, &xdr);
-- 
2.20.1


      parent reply index

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20191001164125.15398-1-sashal@kernel.org>
2019-10-01 16:40 ` [PATCH AUTOSEL 5.2 04/63] fs: nfs: Fix possible null-pointer dereferences in encode_attrs() Sasha Levin
2019-10-01 16:40 ` [PATCH AUTOSEL 5.2 05/63] xprtrdma: Send Queue size grows after a reconnect Sasha Levin
2019-10-01 16:40 ` [PATCH AUTOSEL 5.2 15/63] SUNRPC: RPC level errors should always set task->tk_rpc_status Sasha Levin
2019-10-01 16:40 ` [PATCH AUTOSEL 5.2 20/63] pNFS: Ensure we do clear the return-on-close layout stateid on fatal errors Sasha Levin
2019-10-01 16:40 ` Sasha Levin [this message]

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