[PATCH v5 1/6] net/handshake: Store the key serial number on completion

alistair23
2025-11-12T04:28:17Z

From: Alistair Francis <alistair.francis@wdc.com>

Allow userspace to include a key serial number when completing a
handshake with the HANDSHAKE_CMD_DONE command.

We then store this serial number and will provide it back to userspace
in the future. This allows userspace to save data to the keyring and
then restore that data later.

This will be used to support the TLS KeyUpdate operation, as now
userspace can resume information about a established session.

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Hannes Reincke <hare@suse.de>
---
v5:
- Change name to "handshake session ID"
v4:
- No change
v3:
- No change
v2:
- Change "key-serial" to "session-id"

Documentation/netlink/specs/handshake.yaml | 4 ++++
Documentation/networking/tls-handshake.rst | 1 +
drivers/nvme/host/tcp.c | 3 ++-
drivers/nvme/target/tcp.c | 3 ++-
include/net/handshake.h | 4 +++-
include/uapi/linux/handshake.h | 1 +
net/handshake/genl.c | 5 +++--
net/handshake/tlshd.c | 15 +++++++++++++--
net/sunrpc/svcsock.c | 4 +++-
net/sunrpc/xprtsock.c | 4 +++-
10 files changed, 35 insertions(+), 9 deletions(-)

diff --git a/Documentation/netlink/specs/handshake.yaml b/Documentation/netlink/specs/handshake.yaml
index 95c3fade7a8d..a273bc74d26f 100644
--- a/Documentation/netlink/specs/handshake.yaml
+++ b/Documentation/netlink/specs/handshake.yaml
@@ -87,6 +87,9 @@ attribute-sets:
name: remote-auth
type: u32
multi-attr: true
+ -
+ name: session-id
+ type: u32

operations:
list:
@@ -123,6 +126,7 @@ operations:
- status
- sockfd
- remote-auth
+ - session-id

mcast-groups:
list:
diff --git a/Documentation/networking/tls-handshake.rst b/Documentation/networking/tls-handshake.rst
index 6f5ea1646a47..0941b81dde5c 100644
--- a/Documentation/networking/tls-handshake.rst
+++ b/Documentation/networking/tls-handshake.rst
@@ -60,6 +60,7 @@ fills in a structure that contains the parameters of the request:
key_serial_t ta_my_privkey;
unsigned int ta_num_peerids;
key_serial_t ta_my_peerids[5];
+ key_serial_t handshake_session_id;
};

The @ta_sock field references an open and connected socket. The consumer
diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 9058ea64b89c..024d02248831 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -1694,7 +1694,8 @@ static void nvme_tcp_set_queue_io_cpu(struct nvme_tcp_queue *queue)
qid, queue->io_cpu);
}

-static void nvme_tcp_tls_done(void *data, int status, key_serial_t pskid)
+static void nvme_tcp_tls_done(void *data, int status, key_serial_t pskid,
+ key_serial_t handshake_session_id)
{
struct nvme_tcp_queue *queue = data;
struct nvme_tcp_ctrl *ctrl = queue->ctrl;
diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c
index 470bf37e5a63..7f8516892359 100644
--- a/drivers/nvme/target/tcp.c
+++ b/drivers/nvme/target/tcp.c
@@ -1780,7 +1780,8 @@ static int nvmet_tcp_tls_key_lookup(struct nvmet_tcp_queue *queue,
}

static void nvmet_tcp_tls_handshake_done(void *data, int status,
- key_serial_t peerid)
+ key_serial_t peerid,
+ key_serial_t handshake_session_id)
{
struct nvmet_tcp_queue *queue = data;

diff --git a/include/net/handshake.h b/include/net/handshake.h
index 8ebd4f9ed26e..68d7f89e431a 100644
--- a/include/net/handshake.h
+++ b/include/net/handshake.h
@@ -18,7 +18,8 @@ enum {
};

typedef void (*tls_done_func_t)(void *data, int status,
- key_serial_t peerid);
+ key_serial_t peerid,
+ key_serial_t handshake_session_id);

struct tls_handshake_args {
struct socket *ta_sock;
@@ -31,6 +32,7 @@ struct tls_handshake_args {
key_serial_t ta_my_privkey;
unsigned int ta_num_peerids;
key_serial_t ta_my_peerids[5];
+ key_serial_t handshake_session_id;
};

int tls_client_hello_anon(const struct tls_handshake_args *args, gfp_t flags);
diff --git a/include/uapi/linux/handshake.h b/include/uapi/linux/handshake.h
index 662e7de46c54..b68ffbaa5f31 100644
--- a/include/uapi/linux/handshake.h
+++ b/include/uapi/linux/handshake.h
@@ -55,6 +55,7 @@ enum {
HANDSHAKE_A_DONE_STATUS = 1,
HANDSHAKE_A_DONE_SOCKFD,
HANDSHAKE_A_DONE_REMOTE_AUTH,
+ HANDSHAKE_A_DONE_SESSION_ID,

__HANDSHAKE_A_DONE_MAX,
HANDSHAKE_A_DONE_MAX = (__HANDSHAKE_A_DONE_MAX - 1)
diff --git a/net/handshake/genl.c b/net/handshake/genl.c
index f55d14d7b726..6cdce7e5dbc0 100644
--- a/net/handshake/genl.c
+++ b/net/handshake/genl.c
@@ -16,10 +16,11 @@ static const struct nla_policy handshake_accept_nl_policy[HANDSHAKE_A_ACCEPT_HAN
};

/* HANDSHAKE_CMD_DONE - do */
-static const struct nla_policy handshake_done_nl_policy[HANDSHAKE_A_DONE_REMOTE_AUTH + 1] = {
+static const struct nla_policy handshake_done_nl_policy[HANDSHAKE_A_DONE_SESSION_ID + 1] = {
[HANDSHAKE_A_DONE_STATUS] = { .type = NLA_U32, },
[HANDSHAKE_A_DONE_SOCKFD] = { .type = NLA_S32, },
[HANDSHAKE_A_DONE_REMOTE_AUTH] = { .type = NLA_U32, },
+ [HANDSHAKE_A_DONE_SESSION_ID] = { .type = NLA_U32, },
};

/* Ops table for handshake */
@@ -35,7 +36,7 @@ static const struct genl_split_ops handshake_nl_ops[] = {
.cmd = HANDSHAKE_CMD_DONE,
.doit = handshake_nl_done_doit,
.policy = handshake_done_nl_policy,
- .maxattr = HANDSHAKE_A_DONE_REMOTE_AUTH,
+ .maxattr = HANDSHAKE_A_DONE_SESSION_ID,
.flags = GENL_CMD_CAP_DO,
},
};
diff --git a/net/handshake/tlshd.c b/net/handshake/tlshd.c
index 081093dfd553..85c5fed690c0 100644
--- a/net/handshake/tlshd.c
+++ b/net/handshake/tlshd.c
@@ -26,7 +26,8 @@

struct tls_handshake_req {
void (*th_consumer_done)(void *data, int status,
- key_serial_t peerid);
+ key_serial_t peerid,
+ key_serial_t handshake_session_id);
void *th_consumer_data;

int th_type;
@@ -39,6 +40,8 @@ struct tls_handshake_req {

unsigned int th_num_peerids;
key_serial_t th_peerid[5];
+
+ key_serial_t handshake_session_id;
};

static struct tls_handshake_req *
@@ -55,6 +58,7 @@ 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;
return treq;
}

@@ -83,6 +87,13 @@ static void tls_handshake_remote_peerids(struct tls_handshake_req *treq,
if (i >= treq->th_num_peerids)
break;
}
+
+ nla_for_each_attr(nla, head, len, rem) {
+ if (nla_type(nla) == HANDSHAKE_A_DONE_SESSION_ID) {
+ treq->handshake_session_id = nla_get_u32(nla);
+ break;
+ }
+ }
}

/**
@@ -105,7 +116,7 @@ static void tls_handshake_done(struct handshake_req *req,
set_bit(HANDSHAKE_F_REQ_SESSION, &req->hr_flags);

treq->th_consumer_done(treq->th_consumer_data, -status,
- treq->th_peerid[0]);
+ treq->th_peerid[0], treq->handshake_session_id);
}

#if IS_ENABLED(CONFIG_KEYS)
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 7b90abc5cf0e..2401b4c757f6 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -444,13 +444,15 @@ static void svc_tcp_kill_temp_xprt(struct svc_xprt *xprt)
* @data: address of xprt to wake
* @status: status of handshake
* @peerid: serial number of key containing the remote peer's identity
+ * @handshake_session_id: serial number of the userspace session ID
*
* If a security policy is specified as an export option, we don't
* have a specific export here to check. So we set a "TLS session
* is present" flag on the xprt and let an upper layer enforce local
* security policy.
*/
-static void svc_tcp_handshake_done(void *data, int status, key_serial_t peerid)
+static void svc_tcp_handshake_done(void *data, int status, key_serial_t peerid,
+ key_serial_t handshake_session_id)
{
struct svc_xprt *xprt = data;
struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 3aa987e7f072..5c6e7543f293 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -2589,9 +2589,11 @@ static int xs_tcp_tls_finish_connecting(struct rpc_xprt *lower_xprt,
* @data: address of xprt to wake
* @status: status of handshake
* @peerid: serial number of key containing the remote's identity
+ * @handshake_session_id: serial number of the userspace session ID
*
*/
-static void xs_tls_handshake_done(void *data, int status, key_serial_t peerid)
+static void xs_tls_handshake_done(void *data, int status, key_serial_t peerid,
+ key_serial_t handshake_session_id)
{
struct rpc_xprt *lower_xprt = data;
struct sock_xprt *lower_transport =
--
2.51.1