[PATCH 1/2] nvme-tcp: sanitize request list handling

[Hannes Reinecke <hare@kernel.org>]

Validate the request in nvme_tcp_handle_r2t() to ensure it's not
part of any list, otherwise a malicious R2T PDU might inject a
loop in request list processing.

Signed-off-by: Hannes Reinecke <hare@kernel.org>
---
 drivers/nvme/host/tcp.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index a9d455c39652..10ccd7cf5b8c 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -452,7 +452,8 @@ nvme_tcp_fetch_request(struct nvme_tcp_queue *queue)
 			return NULL;
 	}
 
-	list_del(&req->entry);
+	list_del_init(&req->entry);
+	init_llist_node(&req->lentry);
 	return req;
 }
 
@@ -560,6 +561,8 @@ static int nvme_tcp_init_request(struct blk_mq_tag_set *set,
 	req->queue = queue;
 	nvme_req(rq)->ctrl = &ctrl->ctrl;
 	nvme_req(rq)->cmd = &pdu->cmd;
+	init_llist_node(&req->lentry);
+	INIT_LIST_HEAD(&req->entry);
 
 	return 0;
 }
@@ -764,6 +767,15 @@ static int nvme_tcp_handle_r2t(struct nvme_tcp_queue *queue,
 		return -EPROTO;
 	}
 
+	if (queue->request == req ||
+	    llist_on_list(&req->lentry) ||
+	    !list_empty(&req->entry)) {
+		dev_err(queue->ctrl->ctrl.device,
+			"req %d unexpected r2t while processing request\n",
+			rq->tag);
+		return -EPROTO;
+	}
+
 	req->pdu_len = 0;
 	req->h2cdata_left = r2t_length;
 	req->h2cdata_offset = r2t_offset;
@@ -772,7 +784,8 @@ static int nvme_tcp_handle_r2t(struct nvme_tcp_queue *queue,
 	nvme_tcp_setup_h2c_data_pdu(req);
 
 	llist_add(&req->lentry, &queue->req_list);
-	queue_work_on(queue->io_cpu, nvme_tcp_wq, &queue->io_work);
+	if (list_empty(&queue->send_list))
+		queue_work_on(queue->io_cpu, nvme_tcp_wq, &queue->io_work);
 
 	return 0;
 }
@@ -2611,6 +2624,8 @@ static void nvme_tcp_submit_async_event(struct nvme_ctrl *arg)
 	ctrl->async_req.offset = 0;
 	ctrl->async_req.curr_bio = NULL;
 	ctrl->async_req.data_len = 0;
+	init_llist_node(&ctrl->async_req.lentry);
+	INIT_LIST_HEAD(&ctrl->async_req.entry);
 
 	nvme_tcp_queue_request(&ctrl->async_req, true);
 }
-- 
2.35.3