linux-kernel - [PATCH AUTOSEL for 4.9 070/156] nvmet-rdma: Fix a possible uninitialized variable dereference

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Date:   Thu, 7 Dec 2017 15:49:12 +0000
From:   alexander.levin@...izon.com
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
Cc:     Sagi Grimberg <sagi@...mberg.me>, alexander.levin@...izon.com
Subject: [PATCH AUTOSEL for 4.9 070/156] nvmet-rdma: Fix a possible
 uninitialized variable dereference

From: Sagi Grimberg <sagi@...mberg.me>

[ Upstream commit b25634e2a051bef4b2524b11adddfbfa6448f6cd ]

When handling a new recv command, we grab a new rsp resource and
check for the queue state being live. In case the queue is not in
live state, we simply restore the rsp back to the free list. However
in this flow we didn't set rsp->queue yet, so we cannot dereference it.

Instead, make sure to initialize rsp->queue (and other rsp members)
as soon as possible so we won't reference uninitialized variables.

Reported-by: Yi Zhang <yizhan@...hat.com>
Reported-by: Raju Rangoju <rajur@...lsio.com>
Reviewed-by: Christoph Hellwig <hch@....de>
Tested-by: Raju Rangoju <rajur@...lsio.com>
Signed-off-by: Sagi Grimberg <sagi@...mberg.me>
Signed-off-by: Sasha Levin <alexander.levin@...izon.com>
---
 drivers/nvme/target/rdma.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
index ca8ddc3fb19e..53bd32550867 100644
--- a/drivers/nvme/target/rdma.c
+++ b/drivers/nvme/target/rdma.c
@@ -703,11 +703,6 @@ static void nvmet_rdma_handle_command(struct nvmet_rdma_queue *queue,
 {
 	u16 status;
 
-	cmd->queue = queue;
-	cmd->n_rdma = 0;
-	cmd->req.port = queue->port;
-
-
 	ib_dma_sync_single_for_cpu(queue->dev->device,
 		cmd->cmd->sge[0].addr, cmd->cmd->sge[0].length,
 		DMA_FROM_DEVICE);
@@ -760,9 +755,12 @@ static void nvmet_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc)
 
 	cmd->queue = queue;
 	rsp = nvmet_rdma_get_rsp(queue);
+	rsp->queue = queue;
 	rsp->cmd = cmd;
 	rsp->flags = 0;
 	rsp->req.cmd = cmd->nvme_cmd;
+	rsp->req.port = queue->port;
+	rsp->n_rdma = 0;
 
 	if (unlikely(queue->state != NVMET_RDMA_Q_LIVE)) {
 		unsigned long flags;
-- 
2.11.0