Message-ID: <f5178593-c308-496d-92d5-2a4b5f16be8f@oracle.com>
Date: Thu, 13 Nov 2025 09:41:49 -0500
From: Chuck Lever <chuck.lever@...cle.com>
To: alistair23@...il.com, hare@...nel.org,
        kernel-tls-handshake@...ts.linux.dev, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org,
        linux-nvme@...ts.infradead.org, linux-nfs@...r.kernel.org
Cc: kbusch@...nel.org, axboe@...nel.dk, hch@....de, sagi@...mberg.me,
        kch@...dia.com, hare@...e.de,
        Alistair Francis <alistair.francis@....com>
Subject: Re: [PATCH v5 4/6] net/handshake: Support KeyUpdate message types

On 11/11/25 11:27 PM, alistair23@...il.com wrote:
> From: Alistair Francis <alistair.francis@....com>
> 
> When reporting the msg-type to userspace let's also support reporting
> KeyUpdate events. This supports reporting a client/server event and if
> the other side requested a KeyUpdateRequest.
> 
> Link: https://datatracker.ietf.org/doc/html/rfc8446#section-4.6.3
> Signed-off-by: Alistair Francis <alistair.francis@....com>
> ---
> v5:
>  - Drop clientkeyupdaterequest and serverkeyupdaterequest
> v4:
>  - Don't overload existing functions, instead create new ones
> v3:
>  - Fixup yamllint and kernel-doc failures
> 
>  Documentation/netlink/specs/handshake.yaml | 16 ++++-
>  drivers/nvme/host/tcp.c                    | 15 +++-
>  drivers/nvme/target/tcp.c                  | 10 ++-
>  include/net/handshake.h                    |  6 ++
>  include/uapi/linux/handshake.h             | 11 +++
>  net/handshake/tlshd.c                      | 83 +++++++++++++++++++++-
>  6 files changed, 133 insertions(+), 8 deletions(-)
> 
> diff --git a/Documentation/netlink/specs/handshake.yaml b/Documentation/netlink/specs/handshake.yaml
> index a273bc74d26f..2f77216c8ddf 100644
> --- a/Documentation/netlink/specs/handshake.yaml
> +++ b/Documentation/netlink/specs/handshake.yaml
> @@ -21,12 +21,18 @@ definitions:
>      type: enum
>      name: msg-type
>      value-start: 0
> -    entries: [unspec, clienthello, serverhello]
> +    entries: [unspec, clienthello, serverhello, clientkeyupdate,
> +              serverkeyupdate]
>    -
>      type: enum
>      name: auth
>      value-start: 0
>      entries: [unspec, unauth, psk, x509]
> +  -
> +    type: enum
> +    name: key-update-type
> +    value-start: 0
> +    entries: [unspec, send, received, received_request_update]
>  
>  attribute-sets:
>    -
> @@ -74,6 +80,13 @@ attribute-sets:
>        -
>          name: keyring
>          type: u32
> +      -
> +        name: key-update-request
> +        type: u32
> +        enum: key-update-type
> +      -
> +        name: session-id
> +        type: u32
>    -
>      name: done
>      attributes:
> @@ -116,6 +129,7 @@ operations:
>              - certificate
>              - peername
>              - keyring
> +            - session-id
>      -
>        name: done
>        doc: Handler reports handshake completion
> diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
> index 024d02248831..4797a4532b0d 100644
> --- a/drivers/nvme/host/tcp.c
> +++ b/drivers/nvme/host/tcp.c
> @@ -20,6 +20,7 @@
>  #include <linux/iov_iter.h>
>  #include <net/busy_poll.h>
>  #include <trace/events/sock.h>
> +#include <uapi/linux/handshake.h>
>  
>  #include "nvme.h"
>  #include "fabrics.h"
> @@ -206,6 +207,10 @@ static struct workqueue_struct *nvme_tcp_wq;
>  static const struct blk_mq_ops nvme_tcp_mq_ops;
>  static const struct blk_mq_ops nvme_tcp_admin_mq_ops;
>  static int nvme_tcp_try_send(struct nvme_tcp_queue *queue);
> +static int nvme_tcp_start_tls(struct nvme_ctrl *nctrl,
> +			      struct nvme_tcp_queue *queue,
> +			      key_serial_t pskid,
> +			      enum handshake_key_update_type keyupdate);
>  
>  static inline struct nvme_tcp_ctrl *to_tcp_ctrl(struct nvme_ctrl *ctrl)
>  {
> @@ -1729,7 +1734,8 @@ static void nvme_tcp_tls_done(void *data, int status, key_serial_t pskid,
>  
>  static int nvme_tcp_start_tls(struct nvme_ctrl *nctrl,
>  			      struct nvme_tcp_queue *queue,
> -			      key_serial_t pskid)
> +			      key_serial_t pskid,
> +			      enum handshake_key_update_type keyupdate)
>  {
>  	int qid = nvme_tcp_queue_id(queue);
>  	int ret;
> @@ -1751,7 +1757,10 @@ static int nvme_tcp_start_tls(struct nvme_ctrl *nctrl,
>  	args.ta_timeout_ms = tls_handshake_timeout * 1000;
>  	queue->tls_err = -EOPNOTSUPP;
>  	init_completion(&queue->tls_complete);
> -	ret = tls_client_hello_psk(&args, GFP_KERNEL);
> +	if (keyupdate == HANDSHAKE_KEY_UPDATE_TYPE_UNSPEC)
> +		ret = tls_client_hello_psk(&args, GFP_KERNEL);
> +	else
> +		ret = tls_client_keyupdate_psk(&args, GFP_KERNEL, keyupdate);
>  	if (ret) {
>  		dev_err(nctrl->device, "queue %d: failed to start TLS: %d\n",
>  			qid, ret);
> @@ -1901,7 +1910,7 @@ static int nvme_tcp_alloc_queue(struct nvme_ctrl *nctrl, int qid,
>  
>  	/* If PSKs are configured try to start TLS */
>  	if (nvme_tcp_tls_configured(nctrl) && pskid) {
> -		ret = nvme_tcp_start_tls(nctrl, queue, pskid);
> +		ret = nvme_tcp_start_tls(nctrl, queue, pskid, HANDSHAKE_KEY_UPDATE_TYPE_UNSPEC);
>  		if (ret)
>  			goto err_init_connect;
>  	}
> diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c
> index 7f8516892359..818efdeccef1 100644
> --- a/drivers/nvme/target/tcp.c
> +++ b/drivers/nvme/target/tcp.c
> @@ -1833,7 +1833,8 @@ static void nvmet_tcp_tls_handshake_timeout(struct work_struct *w)
>  	kref_put(&queue->kref, nvmet_tcp_release_queue);
>  }
>  
> -static int nvmet_tcp_tls_handshake(struct nvmet_tcp_queue *queue)
> +static int nvmet_tcp_tls_handshake(struct nvmet_tcp_queue *queue,
> +				   enum handshake_key_update_type keyupdate)
>  {
>  	int ret = -EOPNOTSUPP;
>  	struct tls_handshake_args args;
> @@ -1852,7 +1853,10 @@ static int nvmet_tcp_tls_handshake(struct nvmet_tcp_queue *queue)
>  	args.ta_keyring = key_serial(queue->port->nport->keyring);
>  	args.ta_timeout_ms = tls_handshake_timeout * 1000;
>  
> -	ret = tls_server_hello_psk(&args, GFP_KERNEL);
> +	if (keyupdate == HANDSHAKE_KEY_UPDATE_TYPE_UNSPEC)
> +		ret = tls_server_hello_psk(&args, GFP_KERNEL);
> +	else
> +		ret = tls_server_keyupdate_psk(&args, GFP_KERNEL, keyupdate);
>  	if (ret) {
>  		kref_put(&queue->kref, nvmet_tcp_release_queue);
>  		pr_err("failed to start TLS, err=%d\n", ret);
> @@ -1934,7 +1938,7 @@ static void nvmet_tcp_alloc_queue(struct nvmet_tcp_port *port,
>  		sk->sk_data_ready = port->data_ready;
>  		write_unlock_bh(&sk->sk_callback_lock);
>  		if (!nvmet_tcp_try_peek_pdu(queue)) {
> -			if (!nvmet_tcp_tls_handshake(queue))
> +			if (!nvmet_tcp_tls_handshake(queue, HANDSHAKE_KEY_UPDATE_TYPE_UNSPEC))
>  				return;
>  			/* TLS handshake failed, terminate the connection */
>  			goto out_destroy_sq;
> diff --git a/include/net/handshake.h b/include/net/handshake.h
> index 68d7f89e431a..f5a249327bf6 100644
> --- a/include/net/handshake.h
> +++ b/include/net/handshake.h
> @@ -10,6 +10,8 @@
>  #ifndef _NET_HANDSHAKE_H
>  #define _NET_HANDSHAKE_H
>  
> +#include <uapi/linux/handshake.h>
> +
>  enum {
>  	TLS_NO_KEYRING = 0,
>  	TLS_NO_PEERID = 0,
> @@ -38,8 +40,12 @@ struct tls_handshake_args {
>  int tls_client_hello_anon(const struct tls_handshake_args *args, gfp_t flags);
>  int tls_client_hello_x509(const struct tls_handshake_args *args, gfp_t flags);
>  int tls_client_hello_psk(const struct tls_handshake_args *args, gfp_t flags);
> +int tls_client_keyupdate_psk(const struct tls_handshake_args *args, gfp_t flags,
> +			     enum handshake_key_update_type keyupdate);
>  int tls_server_hello_x509(const struct tls_handshake_args *args, gfp_t flags);
>  int tls_server_hello_psk(const struct tls_handshake_args *args, gfp_t flags);
> +int tls_server_keyupdate_psk(const struct tls_handshake_args *args, gfp_t flags,
> +			     enum handshake_key_update_type keyupdate);
>  
>  bool tls_handshake_cancel(struct sock *sk);
>  void tls_handshake_close(struct socket *sock);
> diff --git a/include/uapi/linux/handshake.h b/include/uapi/linux/handshake.h
> index b68ffbaa5f31..483815a064f0 100644
> --- a/include/uapi/linux/handshake.h
> +++ b/include/uapi/linux/handshake.h
> @@ -19,6 +19,8 @@ enum handshake_msg_type {
>  	HANDSHAKE_MSG_TYPE_UNSPEC,
>  	HANDSHAKE_MSG_TYPE_CLIENTHELLO,
>  	HANDSHAKE_MSG_TYPE_SERVERHELLO,
> +	HANDSHAKE_MSG_TYPE_CLIENTKEYUPDATE,
> +	HANDSHAKE_MSG_TYPE_SERVERKEYUPDATE,
>  };
>  
>  enum handshake_auth {
> @@ -28,6 +30,13 @@ enum handshake_auth {
>  	HANDSHAKE_AUTH_X509,
>  };
>  
> +enum handshake_key_update_type {
> +	HANDSHAKE_KEY_UPDATE_TYPE_UNSPEC,
> +	HANDSHAKE_KEY_UPDATE_TYPE_SEND,
> +	HANDSHAKE_KEY_UPDATE_TYPE_RECEIVED,
> +	HANDSHAKE_KEY_UPDATE_TYPE_RECEIVED_REQUEST_UPDATE,
> +};
> +
>  enum {
>  	HANDSHAKE_A_X509_CERT = 1,
>  	HANDSHAKE_A_X509_PRIVKEY,
> @@ -46,6 +55,8 @@ enum {
>  	HANDSHAKE_A_ACCEPT_CERTIFICATE,
>  	HANDSHAKE_A_ACCEPT_PEERNAME,
>  	HANDSHAKE_A_ACCEPT_KEYRING,
> +	HANDSHAKE_A_ACCEPT_KEY_UPDATE_REQUEST,
> +	HANDSHAKE_A_ACCEPT_SESSION_ID,
>  
>  	__HANDSHAKE_A_ACCEPT_MAX,
>  	HANDSHAKE_A_ACCEPT_MAX = (__HANDSHAKE_A_ACCEPT_MAX - 1)
> diff --git a/net/handshake/tlshd.c b/net/handshake/tlshd.c
> index 85c5fed690c0..91d2bb515b7d 100644
> --- a/net/handshake/tlshd.c
> +++ b/net/handshake/tlshd.c
> @@ -41,6 +41,7 @@ struct tls_handshake_req {
>  	unsigned int		th_num_peerids;
>  	key_serial_t		th_peerid[5];
>  
> +	unsigned int		th_key_update_request;
>  	key_serial_t		handshake_session_id;
>  };
>  
> @@ -58,7 +59,8 @@ tls_handshake_req_init(struct handshake_req *req,
>  	treq->th_num_peerids = 0;
>  	treq->th_certificate = TLS_NO_CERT;
>  	treq->th_privkey = TLS_NO_PRIVKEY;
> -	treq->handshake_session_id = TLS_NO_PRIVKEY;
> +	treq->handshake_session_id = args->handshake_session_id;

Should you initialize the new th_key_update_request field to 0 here?
Prevent leaking previous memory contents to user space...

Reviewed-by: Chuck Lever <chuck.lever@...cle.com>


> +
>  	return treq;
>  }
>  
> @@ -265,6 +267,16 @@ static int tls_handshake_accept(struct handshake_req *req,
>  		break;
>  	}
>  
> +	ret = nla_put_u32(msg, HANDSHAKE_A_ACCEPT_SESSION_ID,
> +			  treq->handshake_session_id);
> +	if (ret < 0)
> +		goto out_cancel;
> +
> +	ret = nla_put_u32(msg, HANDSHAKE_A_ACCEPT_KEY_UPDATE_REQUEST,
> +			  treq->th_key_update_request);
> +	if (ret < 0)
> +		goto out_cancel;
> +
>  	genlmsg_end(msg, hdr);
>  	return genlmsg_reply(msg, info);
>  
> @@ -372,6 +384,44 @@ int tls_client_hello_psk(const struct tls_handshake_args *args, gfp_t flags)
>  }
>  EXPORT_SYMBOL(tls_client_hello_psk);
>  
> +/**
> + * tls_client_keyupdate_psk - request a PSK-based TLS handshake on a socket
> + * @args: socket and handshake parameters for this request
> + * @flags: memory allocation control flags
> + * @keyupdate: specifies the type of KeyUpdate operation
> + *
> + * Return values:
> + *   %0: Handshake request enqueue; ->done will be called when complete
> + *   %-EINVAL: Wrong number of local peer IDs
> + *   %-ESRCH: No user agent is available
> + *   %-ENOMEM: Memory allocation failed
> + */
> +int tls_client_keyupdate_psk(const struct tls_handshake_args *args, gfp_t flags,
> +			     enum handshake_key_update_type keyupdate)
> +{
> +	struct tls_handshake_req *treq;
> +	struct handshake_req *req;
> +	unsigned int i;
> +
> +	if (!args->ta_num_peerids ||
> +	    args->ta_num_peerids > ARRAY_SIZE(treq->th_peerid))
> +		return -EINVAL;
> +
> +	req = handshake_req_alloc(&tls_handshake_proto, flags);
> +	if (!req)
> +		return -ENOMEM;
> +	treq = tls_handshake_req_init(req, args);
> +	treq->th_type = HANDSHAKE_MSG_TYPE_CLIENTKEYUPDATE;
> +	treq->th_key_update_request = keyupdate;
> +	treq->th_auth_mode = HANDSHAKE_AUTH_PSK;
> +	treq->th_num_peerids = args->ta_num_peerids;
> +	for (i = 0; i < args->ta_num_peerids; i++)
> +		treq->th_peerid[i] = args->ta_my_peerids[i];
> +
> +	return handshake_req_submit(args->ta_sock, req, flags);
> +}
> +EXPORT_SYMBOL(tls_client_keyupdate_psk);
> +
>  /**
>   * tls_server_hello_x509 - request a server TLS handshake on a socket
>   * @args: socket and handshake parameters for this request
> @@ -428,6 +478,37 @@ int tls_server_hello_psk(const struct tls_handshake_args *args, gfp_t flags)
>  }
>  EXPORT_SYMBOL(tls_server_hello_psk);
>  
> +/**
> + * tls_server_keyupdate_psk - request a server TLS KeyUpdate on a socket
> + * @args: socket and handshake parameters for this request
> + * @flags: memory allocation control flags
> + * @keyupdate: specifies the type of KeyUpdate operation
> + *
> + * Return values:
> + *   %0: Handshake request enqueue; ->done will be called when complete
> + *   %-ESRCH: No user agent is available
> + *   %-ENOMEM: Memory allocation failed
> + */
> +int tls_server_keyupdate_psk(const struct tls_handshake_args *args, gfp_t flags,
> +			     enum handshake_key_update_type keyupdate)
> +{
> +	struct tls_handshake_req *treq;
> +	struct handshake_req *req;
> +
> +	req = handshake_req_alloc(&tls_handshake_proto, flags);
> +	if (!req)
> +		return -ENOMEM;
> +	treq = tls_handshake_req_init(req, args);
> +	treq->th_type = HANDSHAKE_MSG_TYPE_SERVERKEYUPDATE;
> +	treq->th_key_update_request = keyupdate;
> +	treq->th_auth_mode = HANDSHAKE_AUTH_PSK;
> +	treq->th_num_peerids = 1;
> +	treq->th_peerid[0] = args->ta_my_peerids[0];
> +
> +	return handshake_req_submit(args->ta_sock, req, flags);
> +}
> +EXPORT_SYMBOL(tls_server_keyupdate_psk);
> +
>  /**
>   * tls_handshake_cancel - cancel a pending handshake
>   * @sk: socket on which there is an ongoing handshake


-- 
Chuck Lever

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