From: Sagi Grimberg <sagi@grimberg.me>

Date: Mon, 15 Mar 2021 14:08:11 -0700

Subject: [PATCH] nvme-tcp: fix a NULL deref when receiving a 0-length r2t PDU

Git-commit: fd0823f405090f9f410fc3e3ff7efb52e7b486fa

Patch-mainline: v5.12-rc1

References: git-fixes

When the controller sends us a 0-length r2t PDU we should not attempt to

try to set up a h2cdata PDU but rather conclude that this is a buggy

controller (forward progress is not possible) and simply fail it

immediately.

Fixes: 3f2304f8c6d6 ("nvme-tcp: add NVMe over TCP host driver")

Reported-by: Belanger, Martin <Martin.Belanger@dell.com>

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>

Signed-off-by: Christoph Hellwig <hch@lst.de>

Acked-by: Hannes Reinecke <hare@suse.com>

---

 drivers/nvme/host/tcp.c | 7 +++++++

 1 file changed, 7 insertions(+)

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c

index c535836e7065..5b23e1d52cb3 100644

--- a/drivers/nvme/host/tcp.c

+++ b/drivers/nvme/host/tcp.c

@@ -568,6 +568,13 @@ static int nvme_tcp_setup_h2c_data_pdu(struct nvme_tcp_request *req,

 	req->pdu_len = le32_to_cpu(pdu->r2t_length);

 	req->pdu_sent = 0;

+	if (unlikely(!req->pdu_len)) {

+		dev_err(queue->ctrl->ctrl.device,

+			"req %d r2t len is %u, probably a bug...\n",

+			rq->tag, req->pdu_len);

+		return -EPROTO;

+	}

+

 	if (unlikely(req->data_sent + req->pdu_len > req->data_len)) {

 		dev_err(queue->ctrl->ctrl.device,

 			"req %d r2t len %u exceeded data len %u (%zu sent)\n",

-- 

2.29.2