[PATCH 09/14] nvme-tcp: control message handling for recvmsg()

[Sagi Grimberg]

On 8/3/23 13:50, Hannes Reinecke wrote:
> 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.
> 
> Signed-off-by: Hannes Reinecke <hare at suse.de>
> Reviewed-by: Sagi Grimberg <sagi at grimberg.me>
> ---
>   drivers/nvme/host/tcp.c | 18 +++++++++++++++++-
>   1 file changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
> index 98400ad5f969..4d0e3de39c26 100644
> --- a/drivers/nvme/host/tcp.c
> +++ b/drivers/nvme/host/tcp.c
> @@ -14,6 +14,7 @@
>   #include <net/sock.h>
>   #include <net/tcp.h>
>   #include <net/tls.h>
> +#include <net/tls_prot.h>
>   #include <net/handshake.h>
>   #include <linux/blk-mq.h>
>   #include <crypto/hash.h>
> @@ -1369,6 +1370,10 @@ static int nvme_tcp_init_connection(struct nvme_tcp_queue *queue)
>   {
>   	struct nvme_tcp_icreq_pdu *icreq;
>   	struct nvme_tcp_icresp_pdu *icresp;
> +#ifdef CONFIG_NVME_TCP_TLS
> +	char cbuf[CMSG_LEN(sizeof(char))] = {};
> +	u8 ctype;
> +#endif
>   	struct msghdr msg = {};
>   	struct kvec iov;
>   	bool ctrl_hdgst, ctrl_ddgst;
> @@ -1406,11 +1411,22 @@ 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);
> +#ifdef CONFIG_NVME_TCP_TLS
> +	msg.msg_control = cbuf;
> +	msg.msg_controllen = sizeof(cbuf);
> +#endif
>   	ret = kernel_recvmsg(queue->sock, &msg, &iov, 1,
>   			iov.iov_len, msg.msg_flags);
>   	if (ret < 0)
>   		goto free_icresp;

Is the cmsg passed unconditionally? meaning this does not
impact non-tls?

If so, why is the ifdef needed?

> -
> +#ifdef CONFIG_NVME_TCP_TLS
> +	ctype = tls_get_record_type(queue->sock->sk, (struct cmsghdr *)cbuf);
> +	if (ctype != TLS_RECORD_TYPE_DATA) {
> +		pr_err("queue %d: unhandled TLS record %d\n",
> +		       nvme_tcp_queue_id(queue), ctype);
> +		return -ENOTCONN;
> +	}
> +#endif



>   	ret = -EINVAL;
>   	if (icresp->hdr.type != nvme_tcp_icresp) {
>   		pr_err("queue %d: bad type returned %d\n",