Re: [PATCH 11/18] nvme-tcp: control message handling for recvmsg()

[Sagi Grimberg <sagi@grimberg.me>]

> kTLS is sending TLS ALERT messages as control messages for recvmsg().
> As we can't do anything sensible with it just abort the connection
> and let the userspace agent to a re-negotiation.

Is this a problem if we do end up adding read_sock to tls?
Although I do see that the tls code does manage this in the
sk_buff control buffer, so I assume there is access to this info.

CC'ing Boris here as well.

> 
> Signed-off-by: Hannes Reinecke <hare@suse.de>
> ---
>   drivers/nvme/host/tcp.c | 68 +++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 68 insertions(+)
> 
> diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
> index 007d457cacf9..e0fc98ac9e05 100644
> --- a/drivers/nvme/host/tcp.c
> +++ b/drivers/nvme/host/tcp.c
> @@ -13,6 +13,7 @@
>   #include <linux/nvme-keyring.h>
>   #include <net/sock.h>
>   #include <net/tcp.h>
> +#include <net/tls.h>
>   #include <net/handshake.h>
>   #include <linux/blk-mq.h>
>   #include <crypto/hash.h>
> @@ -727,7 +728,12 @@ static int nvme_tcp_recv_pdu(struct nvme_tcp_queue *queue, bool pending)
>   {
>   	struct nvme_tcp_hdr *hdr;
>   	size_t rcv_len = queue->pdu_remaining;
> +	char cbuf[CMSG_LEN(sizeof(char))] = {};
> +	struct cmsghdr *cmsg;
> +	unsigned char ctype;
>   	struct msghdr msg = {
> +		.msg_control = cbuf,
> +		.msg_controllen = sizeof(cbuf),
>   		.msg_flags = pending ? 0 : MSG_DONTWAIT,
>   	};
>   	struct kvec iov = {
> @@ -743,6 +749,18 @@ static int nvme_tcp_recv_pdu(struct nvme_tcp_queue *queue, bool pending)
>   			     iov.iov_len, msg.msg_flags);
>   	if (ret <= 0)
>   		return ret;
> +	cmsg = (struct cmsghdr *)cbuf;
> +	if (CMSG_OK(&msg, cmsg) &&
> +	    cmsg->cmsg_level == SOL_TLS &&
> +	    cmsg->cmsg_type == TLS_GET_RECORD_TYPE) {
> +		ctype = *((unsigned char *)CMSG_DATA(cmsg));
> +		if (ctype != TLS_RECORD_TYPE_DATA) {
> +			dev_err(queue->ctrl->ctrl.device,
> +				"queue %d unhandled TLS record %d\n",
> +				nvme_tcp_queue_id(queue), ctype);
> +			return -ENOTCONN;
> +		}
> +	}
>   
>   	rcv_len = ret;
>   	queue->pdu_remaining -= rcv_len;
> @@ -793,6 +811,9 @@ static int nvme_tcp_recv_data(struct nvme_tcp_queue *queue)
>   	struct request *rq =
>   		nvme_cid_to_rq(nvme_tcp_tagset(queue), pdu->command_id);
>   	struct nvme_tcp_request *req = blk_mq_rq_to_pdu(rq);
> +	char cbuf[CMSG_LEN(sizeof(char))];
> +	struct cmsghdr *cmsg;
> +	unsigned char ctype;
>   
>   	if (nvme_tcp_recv_state(queue) != NVME_TCP_RECV_DATA)
>   		return 0;
> @@ -824,6 +845,8 @@ static int nvme_tcp_recv_data(struct nvme_tcp_queue *queue)
>   		/* we can read only from what is left in this bio */
>   		memset(&msg, 0, sizeof(msg));
>   		msg.msg_iter = req->iter;
> +		msg.msg_control = cbuf;
> +		msg.msg_controllen = sizeof(cbuf);
>   
>   		ret = sock_recvmsg(queue->sock, &msg, 0);
>   		if (ret <= 0) {
> @@ -832,6 +855,18 @@ static int nvme_tcp_recv_data(struct nvme_tcp_queue *queue)
>   				nvme_tcp_queue_id(queue), rq->tag);
>   			return ret;
>   		}
> +		cmsg = (struct cmsghdr *)cbuf;
> +		if (CMSG_OK(&msg, cmsg) &&
> +		    cmsg->cmsg_level == SOL_TLS &&
> +		    cmsg->cmsg_type == TLS_GET_RECORD_TYPE) {
> +			ctype = *((unsigned char *)CMSG_DATA(cmsg));
> +			if (ctype != TLS_RECORD_TYPE_DATA) {
> +				dev_err(queue->ctrl->ctrl.device,
> +					"queue %d unhandled TLS record %d\n",
> +					nvme_tcp_queue_id(queue), ctype);
> +				return -ENOTCONN;
> +			}
> +		}
>   
>   		queue->data_remaining -= ret;
>   		if (queue->data_remaining)
> @@ -861,7 +896,12 @@ static int nvme_tcp_recv_ddgst(struct nvme_tcp_queue *queue)
>   	char *ddgst = (char *)&queue->recv_ddgst;
>   	size_t recv_len = queue->ddgst_remaining;
>   	off_t off = NVME_TCP_DIGEST_LENGTH - queue->ddgst_remaining;
> +	char cbuf[CMSG_LEN(sizeof(char))] = {};
> +	struct cmsghdr *cmsg;
> +	unsigned char ctype;
>   	struct msghdr msg = {
> +		.msg_control = cbuf,
> +		.msg_controllen = sizeof(cbuf),
>   		.msg_flags = 0,
>   	};
>   	struct kvec iov = {
> @@ -877,6 +917,18 @@ static int nvme_tcp_recv_ddgst(struct nvme_tcp_queue *queue)
>   			     msg.msg_flags);
>   	if (ret <= 0)
>   		return ret;
> +	cmsg = (struct cmsghdr *)cbuf;
> +	if (CMSG_OK(&msg, cmsg) &&
> +	    cmsg->cmsg_level == SOL_TLS &&
> +	    cmsg->cmsg_type == TLS_GET_RECORD_TYPE) {
> +		ctype = *((unsigned char *)CMSG_DATA(cmsg));
> +		if (ctype != TLS_RECORD_TYPE_DATA) {
> +			dev_err(queue->ctrl->ctrl.device,
> +				"queue %d unhandled TLS record %d\n",
> +				nvme_tcp_queue_id(queue), ctype);
> +			return -ENOTCONN;
> +		}
> +	}
>   
>   	recv_len = ret;
>   	queue->ddgst_remaining -= recv_len;
> @@ -1372,6 +1424,9 @@ static int nvme_tcp_init_connection(struct nvme_tcp_queue *queue)
>   {
>   	struct nvme_tcp_icreq_pdu *icreq;
>   	struct nvme_tcp_icresp_pdu *icresp;
> +	char cbuf[CMSG_LEN(sizeof(char))] = {};
> +	struct cmsghdr *cmsg;
> +	unsigned char ctype;
>   	struct msghdr msg = {};
>   	struct kvec iov;
>   	bool ctrl_hdgst, ctrl_ddgst;
> @@ -1409,10 +1464,23 @@ static int nvme_tcp_init_connection(struct nvme_tcp_queue *queue)
>   	memset(&msg, 0, sizeof(msg));
>   	iov.iov_base = icresp;
>   	iov.iov_len = sizeof(*icresp);
> +	msg.msg_control = cbuf;
> +	msg.msg_controllen = sizeof(cbuf);
>   	ret = kernel_recvmsg(queue->sock, &msg, &iov, 1,
>   			iov.iov_len, msg.msg_flags);
>   	if (ret < 0)
>   		goto free_icresp;
> +	cmsg = (struct cmsghdr *)cbuf;
> +	if (CMSG_OK(&msg, cmsg) &&
> +	    cmsg->cmsg_level == SOL_TLS &&
> +	    cmsg->cmsg_type == TLS_GET_RECORD_TYPE) {
> +		ctype = *((unsigned char *)CMSG_DATA(cmsg));
> +		if (ctype != TLS_RECORD_TYPE_DATA) {
> +			pr_err("queue %d: unhandled TLS record %d\n",
> +			       nvme_tcp_queue_id(queue), ctype);
> +			return -ENOTCONN;
> +		}
> +	}
>   
>   	ret = -EINVAL;
>   	if (icresp->hdr.type != nvme_tcp_icresp) {