From 7fa3f73f6c8ddc5f0425b50fb2a626a782ef7d12 Mon Sep 17 00:00:00 2001 From: Yehyeong Lee Date: Sat, 1 Aug 2026 17:18:17 +0900 Subject: [PATCH] nvme-tcp: reject a read that transferred too few bytes nvme_tcp_recv_data() completes a request once the current C2HData PDU has been consumed. Nothing compares the total bytes received against the length the command asked for: struct nvme_tcp_request has no receive-side counter, queue->data_remaining is per queue, and blk_mq_end_request() completes for blk_rq_bytes(rq) unconditionally with no residual concept anywhere above. A controller can therefore answer a 4096-byte read with 512 bytes and have it reported as a complete read; user space then gets 4096 bytes of which 3584 are whatever was already in the page. I reproduced that with a test target. Count the bytes received and refuse to complete a successful read whose count does not match, at the two NVME_TCP_F_DATA_SUCCESS paths and in nvme_tcp_process_nvme_cqe(). The success test shifts req->status right by one, because the driver keeps the wire value there and shifts it on completion, so the check must see what the completion path will see. Only REQ_OP_READ is checked, because there the length comes from the sectors the request covers; a passthrough command is built by its submitter, which picks both command and buffer, so the kernel has nothing to compare against. Fixes: 3f2304f8c6d6 ("nvme-tcp: add NVMe over TCP host driver") Cc: stable@vger.kernel.org Signed-off-by: Yehyeong Lee Signed-off-by: Keith Busch --- drivers/nvme/host/tcp.c | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c index 1d303e54e13e..3655f7607be0 100644 --- a/drivers/nvme/host/tcp.c +++ b/drivers/nvme/host/tcp.c @@ -80,6 +80,7 @@ struct nvme_tcp_request { struct bio *curr_bio; struct iov_iter iter; + u32 data_recvd; /* send state */ size_t offset; @@ -617,6 +618,29 @@ static void nvme_tcp_error_recovery(struct nvme_ctrl *ctrl) queue_work(nvme_reset_wq, &to_tcp_ctrl(ctrl)->err_work); } +/* + * NVMe has no short read: a read that completes successfully must + * have transferred everything it asked for. + */ +static bool nvme_tcp_data_in_short(struct nvme_tcp_queue *queue, + struct request *rq) +{ + struct nvme_tcp_request *req = blk_mq_rq_to_pdu(rq); + + if (le16_to_cpu(req->status) >> 1) + return false; + if (req_op(rq) != REQ_OP_READ || !req->data_len) + return false; + if (likely(req->data_recvd == req->data_len)) + return false; + + dev_err(queue->ctrl->ctrl.device, + "queue %d tag %#x short data-in: got %u of %u\n", + nvme_tcp_queue_id(queue), rq->tag, + req->data_recvd, req->data_len); + return true; +} + static int nvme_tcp_process_nvme_cqe(struct nvme_tcp_queue *queue, struct nvme_completion *cqe) { @@ -636,6 +660,9 @@ static int nvme_tcp_process_nvme_cqe(struct nvme_tcp_queue *queue, if (req->status == cpu_to_le16(NVME_SC_SUCCESS)) req->status = cqe->status; + if (unlikely(nvme_tcp_data_in_short(queue, rq))) + return -EPROTO; + if (!nvme_try_complete_req(rq, req->status, cqe->result)) nvme_complete_rq(rq); queue->nr_cqe++; @@ -958,6 +985,7 @@ static int nvme_tcp_recv_data(struct nvme_tcp_queue *queue, struct sk_buff *skb, *len -= recv_len; *offset += recv_len; queue->data_remaining -= recv_len; + req->data_recvd += recv_len; } if (!queue->data_remaining) { @@ -966,6 +994,8 @@ static int nvme_tcp_recv_data(struct nvme_tcp_queue *queue, struct sk_buff *skb, queue->ddgst_remaining = NVME_TCP_DIGEST_LENGTH; } else { if (pdu->hdr.flags & NVME_TCP_F_DATA_SUCCESS) { + if (unlikely(nvme_tcp_data_in_short(queue, rq))) + return -EPROTO; nvme_tcp_end_request(rq, le16_to_cpu(req->status)); queue->nr_cqe++; @@ -1014,6 +1044,9 @@ static int nvme_tcp_recv_ddgst(struct nvme_tcp_queue *queue, pdu->command_id); struct nvme_tcp_request *req = blk_mq_rq_to_pdu(rq); + if (unlikely(nvme_tcp_data_in_short(queue, rq))) + return -EPROTO; + nvme_tcp_end_request(rq, le16_to_cpu(req->status)); queue->nr_cqe++; } @@ -2746,6 +2779,7 @@ static blk_status_t nvme_tcp_setup_cmd_pdu(struct nvme_ns *ns, req->status = cpu_to_le16(NVME_SC_SUCCESS); req->offset = 0; req->data_sent = 0; + req->data_recvd = 0; req->pdu_len = 0; req->pdu_sent = 0; req->h2cdata_left = 0;