Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

11 files changed, 1952 insertions, 0 deletions

diff --git a/net/handshake/.kunitconfig b/net/handshake/.kunitconfig
new file mode 100644
index 000000000..5c48cf4ab
--- /dev/null
+++ b/net/handshake/.kunitconfig
@@ -0,0 +1,11 @@
+CONFIG_KUNIT=y
+CONFIG_UBSAN=y
+CONFIG_STACKTRACE=y
+CONFIG_NET=y
+CONFIG_NETWORK_FILESYSTEMS=y
+CONFIG_INET=y
+CONFIG_MULTIUSER=y
+CONFIG_NFS_FS=y
+CONFIG_SUNRPC=y
+CONFIG_NET_HANDSHAKE=y
+CONFIG_NET_HANDSHAKE_KUNIT_TEST=y
diff --git a/net/handshake/Makefile b/net/handshake/Makefile
new file mode 100644
index 000000000..ef4d9a211
--- /dev/null
+++ b/net/handshake/Makefile
@@ -0,0 +1,13 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Makefile for the Generic HANDSHAKE service
+#
+# Author: Chuck Lever <chuck.lever@oracle.com>
+#
+# Copyright (c) 2023, Oracle and/or its affiliates.
+#
+
+obj-y += handshake.o
+handshake-y := alert.o genl.o netlink.o request.o tlshd.o trace.o
+
+obj-$(CONFIG_NET_HANDSHAKE_KUNIT_TEST) += handshake-test.o
diff --git a/net/handshake/alert.c b/net/handshake/alert.c
new file mode 100644
index 000000000..329d91984
--- /dev/null
+++ b/net/handshake/alert.c
@@ -0,0 +1,110 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Handle the TLS Alert protocol
+ *
+ * Author: Chuck Lever <chuck.lever@oracle.com>
+ *
+ * Copyright (c) 2023, Oracle and/or its affiliates.
+ */
+
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/inet.h>
+
+#include <net/sock.h>
+#include <net/handshake.h>
+#include <net/tls.h>
+#include <net/tls_prot.h>
+
+#include "handshake.h"
+
+#include <trace/events/handshake.h>
+
+/**
+ * tls_alert_send - send a TLS Alert on a kTLS socket
+ * @sock: open kTLS socket to send on
+ * @level: TLS Alert level
+ * @description: TLS Alert description
+ *
+ * Returns zero on success or a negative errno.
+ */
+int tls_alert_send(struct socket *sock, u8 level, u8 description)
+{
+	u8 record_type = TLS_RECORD_TYPE_ALERT;
+	u8 buf[CMSG_SPACE(sizeof(record_type))];
+	struct msghdr msg = { 0 };
+	struct cmsghdr *cmsg;
+	struct kvec iov;
+	u8 alert[2];
+	int ret;
+
+	trace_tls_alert_send(sock->sk, level, description);
+
+	alert[0] = level;
+	alert[1] = description;
+	iov.iov_base = alert;
+	iov.iov_len = sizeof(alert);
+
+	memset(buf, 0, sizeof(buf));
+	msg.msg_control = buf;
+	msg.msg_controllen = sizeof(buf);
+	msg.msg_flags = MSG_DONTWAIT;
+
+	cmsg = CMSG_FIRSTHDR(&msg);
+	cmsg->cmsg_level = SOL_TLS;
+	cmsg->cmsg_type = TLS_SET_RECORD_TYPE;
+	cmsg->cmsg_len = CMSG_LEN(sizeof(record_type));
+	memcpy(CMSG_DATA(cmsg), &record_type, sizeof(record_type));
+
+	iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, &iov, 1, iov.iov_len);
+	ret = sock_sendmsg(sock, &msg);
+	return ret < 0 ? ret : 0;
+}
+
+/**
+ * tls_get_record_type - Look for TLS RECORD_TYPE information
+ * @sk: socket (for IP address information)
+ * @cmsg: incoming message to be parsed
+ *
+ * Returns zero or a TLS_RECORD_TYPE value.
+ */
+u8 tls_get_record_type(const struct sock *sk, const struct cmsghdr *cmsg)
+{
+	u8 record_type;
+
+	if (cmsg->cmsg_level != SOL_TLS)
+		return 0;
+	if (cmsg->cmsg_type != TLS_GET_RECORD_TYPE)
+		return 0;
+
+	record_type = *((u8 *)CMSG_DATA(cmsg));
+	trace_tls_contenttype(sk, record_type);
+	return record_type;
+}
+EXPORT_SYMBOL(tls_get_record_type);
+
+/**
+ * tls_alert_recv - Parse TLS Alert messages
+ * @sk: socket (for IP address information)
+ * @msg: incoming message to be parsed
+ * @level: OUT - TLS AlertLevel value
+ * @description: OUT - TLS AlertDescription value
+ *
+ */
+void tls_alert_recv(const struct sock *sk, const struct msghdr *msg,
+		    u8 *level, u8 *description)
+{
+	const struct kvec *iov;
+	u8 *data;
+
+	iov = msg->msg_iter.kvec;
+	data = iov->iov_base;
+	*level = data[0];
+	*description = data[1];
+
+	trace_tls_alert_recv(sk, *level, *description);
+}
+EXPORT_SYMBOL(tls_alert_recv);
diff --git a/net/handshake/genl.c b/net/handshake/genl.c
new file mode 100644
index 000000000..233be5cbf
--- /dev/null
+++ b/net/handshake/genl.c
@@ -0,0 +1,58 @@
+// SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
+/* Do not edit directly, auto-generated from: */
+/*	Documentation/netlink/specs/handshake.yaml */
+/* YNL-GEN kernel source */
+
+#include <net/netlink.h>
+#include <net/genetlink.h>
+
+#include "genl.h"
+
+#include <uapi/linux/handshake.h>
+
+/* HANDSHAKE_CMD_ACCEPT - do */
+static const struct nla_policy handshake_accept_nl_policy[HANDSHAKE_A_ACCEPT_HANDLER_CLASS + 1] = {
+	[HANDSHAKE_A_ACCEPT_HANDLER_CLASS] = NLA_POLICY_MAX(NLA_U32, 2),
+};
+
+/* HANDSHAKE_CMD_DONE - do */
+static const struct nla_policy handshake_done_nl_policy[HANDSHAKE_A_DONE_REMOTE_AUTH + 1] = {
+	[HANDSHAKE_A_DONE_STATUS] = { .type = NLA_U32, },
+	[HANDSHAKE_A_DONE_SOCKFD] = { .type = NLA_U32, },
+	[HANDSHAKE_A_DONE_REMOTE_AUTH] = { .type = NLA_U32, },
+};
+
+/* Ops table for handshake */
+static const struct genl_split_ops handshake_nl_ops[] = {
+	{
+		.cmd		= HANDSHAKE_CMD_ACCEPT,
+		.doit		= handshake_nl_accept_doit,
+		.policy		= handshake_accept_nl_policy,
+		.maxattr	= HANDSHAKE_A_ACCEPT_HANDLER_CLASS,
+		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
+	},
+	{
+		.cmd		= HANDSHAKE_CMD_DONE,
+		.doit		= handshake_nl_done_doit,
+		.policy		= handshake_done_nl_policy,
+		.maxattr	= HANDSHAKE_A_DONE_REMOTE_AUTH,
+		.flags		= GENL_CMD_CAP_DO,
+	},
+};
+
+static const struct genl_multicast_group handshake_nl_mcgrps[] = {
+	[HANDSHAKE_NLGRP_NONE] = { "none", },
+	[HANDSHAKE_NLGRP_TLSHD] = { "tlshd", },
+};
+
+struct genl_family handshake_nl_family __ro_after_init = {
+	.name		= HANDSHAKE_FAMILY_NAME,
+	.version	= HANDSHAKE_FAMILY_VERSION,
+	.netnsok	= true,
+	.parallel_ops	= true,
+	.module		= THIS_MODULE,
+	.split_ops	= handshake_nl_ops,
+	.n_split_ops	= ARRAY_SIZE(handshake_nl_ops),
+	.mcgrps		= handshake_nl_mcgrps,
+	.n_mcgrps	= ARRAY_SIZE(handshake_nl_mcgrps),
+};
diff --git a/net/handshake/genl.h b/net/handshake/genl.h
new file mode 100644
index 000000000..ae72a596f
--- /dev/null
+++ b/net/handshake/genl.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) */
+/* Do not edit directly, auto-generated from: */
+/*	Documentation/netlink/specs/handshake.yaml */
+/* YNL-GEN kernel header */
+
+#ifndef _LINUX_HANDSHAKE_GEN_H
+#define _LINUX_HANDSHAKE_GEN_H
+
+#include <net/netlink.h>
+#include <net/genetlink.h>
+
+#include <uapi/linux/handshake.h>
+
+int handshake_nl_accept_doit(struct sk_buff *skb, struct genl_info *info);
+int handshake_nl_done_doit(struct sk_buff *skb, struct genl_info *info);
+
+enum {
+	HANDSHAKE_NLGRP_NONE,
+	HANDSHAKE_NLGRP_TLSHD,
+};
+
+extern struct genl_family handshake_nl_family;
+
+#endif /* _LINUX_HANDSHAKE_GEN_H */
diff --git a/net/handshake/handshake-test.c b/net/handshake/handshake-test.c
new file mode 100644
index 000000000..16ed7bfd2
--- /dev/null
+++ b/net/handshake/handshake-test.c
@@ -0,0 +1,537 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2023 Oracle and/or its affiliates.
+ *
+ * KUnit test of the handshake upcall mechanism.
+ */
+
+#include <kunit/test.h>
+#include <kunit/visibility.h>
+
+#include <linux/kernel.h>
+
+#include <net/sock.h>
+#include <net/genetlink.h>
+#include <net/netns/generic.h>
+
+#include <uapi/linux/handshake.h>
+#include "handshake.h"
+
+MODULE_IMPORT_NS(EXPORTED_FOR_KUNIT_TESTING);
+
+static int test_accept_func(struct handshake_req *req, struct genl_info *info,
+			    int fd)
+{
+	return 0;
+}
+
+static void test_done_func(struct handshake_req *req, unsigned int status,
+			   struct genl_info *info)
+{
+}
+
+struct handshake_req_alloc_test_param {
+	const char			*desc;
+	struct handshake_proto		*proto;
+	gfp_t				gfp;
+	bool				expect_success;
+};
+
+static struct handshake_proto handshake_req_alloc_proto_2 = {
+	.hp_handler_class	= HANDSHAKE_HANDLER_CLASS_NONE,
+};
+
+static struct handshake_proto handshake_req_alloc_proto_3 = {
+	.hp_handler_class	= HANDSHAKE_HANDLER_CLASS_MAX,
+};
+
+static struct handshake_proto handshake_req_alloc_proto_4 = {
+	.hp_handler_class	= HANDSHAKE_HANDLER_CLASS_TLSHD,
+};
+
+static struct handshake_proto handshake_req_alloc_proto_5 = {
+	.hp_handler_class	= HANDSHAKE_HANDLER_CLASS_TLSHD,
+	.hp_accept		= test_accept_func,
+};
+
+static struct handshake_proto handshake_req_alloc_proto_6 = {
+	.hp_handler_class	= HANDSHAKE_HANDLER_CLASS_TLSHD,
+	.hp_privsize		= UINT_MAX,
+	.hp_accept		= test_accept_func,
+	.hp_done		= test_done_func,
+};
+
+static struct handshake_proto handshake_req_alloc_proto_good = {
+	.hp_handler_class	= HANDSHAKE_HANDLER_CLASS_TLSHD,
+	.hp_accept		= test_accept_func,
+	.hp_done		= test_done_func,
+};
+
+static const
+struct handshake_req_alloc_test_param handshake_req_alloc_params[] = {
+	{
+		.desc			= "handshake_req_alloc NULL proto",
+		.proto			= NULL,
+		.gfp			= GFP_KERNEL,
+		.expect_success		= false,
+	},
+	{
+		.desc			= "handshake_req_alloc CLASS_NONE",
+		.proto			= &handshake_req_alloc_proto_2,
+		.gfp			= GFP_KERNEL,
+		.expect_success		= false,
+	},
+	{
+		.desc			= "handshake_req_alloc CLASS_MAX",
+		.proto			= &handshake_req_alloc_proto_3,
+		.gfp			= GFP_KERNEL,
+		.expect_success		= false,
+	},
+	{
+		.desc			= "handshake_req_alloc no callbacks",
+		.proto			= &handshake_req_alloc_proto_4,
+		.gfp			= GFP_KERNEL,
+		.expect_success		= false,
+	},
+	{
+		.desc			= "handshake_req_alloc no done callback",
+		.proto			= &handshake_req_alloc_proto_5,
+		.gfp			= GFP_KERNEL,
+		.expect_success		= false,
+	},
+	{
+		.desc			= "handshake_req_alloc excessive privsize",
+		.proto			= &handshake_req_alloc_proto_6,
+		.gfp			= GFP_KERNEL | __GFP_NOWARN,
+		.expect_success		= false,
+	},
+	{
+		.desc			= "handshake_req_alloc all good",
+		.proto			= &handshake_req_alloc_proto_good,
+		.gfp			= GFP_KERNEL,
+		.expect_success		= true,
+	},
+};
+
+static void
+handshake_req_alloc_get_desc(const struct handshake_req_alloc_test_param *param,
+			     char *desc)
+{
+	strscpy(desc, param->desc, KUNIT_PARAM_DESC_SIZE);
+}
+
+/* Creates the function handshake_req_alloc_gen_params */
+KUNIT_ARRAY_PARAM(handshake_req_alloc, handshake_req_alloc_params,
+		  handshake_req_alloc_get_desc);
+
+static void handshake_req_alloc_case(struct kunit *test)
+{
+	const struct handshake_req_alloc_test_param *param = test->param_value;
+	struct handshake_req *result;
+
+	/* Arrange */
+
+	/* Act */
+	result = handshake_req_alloc(param->proto, param->gfp);
+
+	/* Assert */
+	if (param->expect_success)
+		KUNIT_EXPECT_NOT_NULL(test, result);
+	else
+		KUNIT_EXPECT_NULL(test, result);
+
+	kfree(result);
+}
+
+static void handshake_req_submit_test1(struct kunit *test)
+{
+	struct socket *sock;
+	int err, result;
+
+	/* Arrange */
+	err = __sock_create(&init_net, PF_INET, SOCK_STREAM, IPPROTO_TCP,
+			    &sock, 1);
+	KUNIT_ASSERT_EQ(test, err, 0);
+
+	/* Act */
+	result = handshake_req_submit(sock, NULL, GFP_KERNEL);
+
+	/* Assert */
+	KUNIT_EXPECT_EQ(test, result, -EINVAL);
+
+	sock_release(sock);
+}
+
+static void handshake_req_submit_test2(struct kunit *test)
+{
+	struct handshake_req *req;
+	int result;
+
+	/* Arrange */
+	req = handshake_req_alloc(&handshake_req_alloc_proto_good, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, req);
+
+	/* Act */
+	result = handshake_req_submit(NULL, req, GFP_KERNEL);
+
+	/* Assert */
+	KUNIT_EXPECT_EQ(test, result, -EINVAL);
+
+	/* handshake_req_submit() destroys @req on error */
+}
+
+static void handshake_req_submit_test3(struct kunit *test)
+{
+	struct handshake_req *req;
+	struct socket *sock;
+	int err, result;
+
+	/* Arrange */
+	req = handshake_req_alloc(&handshake_req_alloc_proto_good, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, req);
+
+	err = __sock_create(&init_net, PF_INET, SOCK_STREAM, IPPROTO_TCP,
+			    &sock, 1);
+	KUNIT_ASSERT_EQ(test, err, 0);
+	sock->file = NULL;
+
+	/* Act */
+	result = handshake_req_submit(sock, req, GFP_KERNEL);
+
+	/* Assert */
+	KUNIT_EXPECT_EQ(test, result, -EINVAL);
+
+	/* handshake_req_submit() destroys @req on error */
+	sock_release(sock);
+}
+
+static void handshake_req_submit_test4(struct kunit *test)
+{
+	struct handshake_req *req, *result;
+	struct socket *sock;
+	struct file *filp;
+	int err;
+
+	/* Arrange */
+	req = handshake_req_alloc(&handshake_req_alloc_proto_good, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, req);
+
+	err = __sock_create(&init_net, PF_INET, SOCK_STREAM, IPPROTO_TCP,
+			    &sock, 1);
+	KUNIT_ASSERT_EQ(test, err, 0);
+	filp = sock_alloc_file(sock, O_NONBLOCK, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, filp);
+	KUNIT_ASSERT_NOT_NULL(test, sock->sk);
+	sock->file = filp;
+
+	err = handshake_req_submit(sock, req, GFP_KERNEL);
+	KUNIT_ASSERT_EQ(test, err, 0);
+
+	/* Act */
+	result = handshake_req_hash_lookup(sock->sk);
+
+	/* Assert */
+	KUNIT_EXPECT_NOT_NULL(test, result);
+	KUNIT_EXPECT_PTR_EQ(test, req, result);
+
+	handshake_req_cancel(sock->sk);
+	fput(filp);
+}
+
+static void handshake_req_submit_test5(struct kunit *test)
+{
+	struct handshake_req *req;
+	struct handshake_net *hn;
+	struct socket *sock;
+	struct file *filp;
+	struct net *net;
+	int saved, err;
+
+	/* Arrange */
+	req = handshake_req_alloc(&handshake_req_alloc_proto_good, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, req);
+
+	err = __sock_create(&init_net, PF_INET, SOCK_STREAM, IPPROTO_TCP,
+			    &sock, 1);
+	KUNIT_ASSERT_EQ(test, err, 0);
+	filp = sock_alloc_file(sock, O_NONBLOCK, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, filp);
+	KUNIT_ASSERT_NOT_NULL(test, sock->sk);
+	sock->file = filp;
+
+	net = sock_net(sock->sk);
+	hn = handshake_pernet(net);
+	KUNIT_ASSERT_NOT_NULL(test, hn);
+
+	saved = hn->hn_pending;
+	hn->hn_pending = hn->hn_pending_max + 1;
+
+	/* Act */
+	err = handshake_req_submit(sock, req, GFP_KERNEL);
+
+	/* Assert */
+	KUNIT_EXPECT_EQ(test, err, -EAGAIN);
+
+	fput(filp);
+	hn->hn_pending = saved;
+}
+
+static void handshake_req_submit_test6(struct kunit *test)
+{
+	struct handshake_req *req1, *req2;
+	struct socket *sock;
+	struct file *filp;
+	int err;
+
+	/* Arrange */
+	req1 = handshake_req_alloc(&handshake_req_alloc_proto_good, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, req1);
+	req2 = handshake_req_alloc(&handshake_req_alloc_proto_good, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, req2);
+
+	err = __sock_create(&init_net, PF_INET, SOCK_STREAM, IPPROTO_TCP,
+			    &sock, 1);
+	KUNIT_ASSERT_EQ(test, err, 0);
+	filp = sock_alloc_file(sock, O_NONBLOCK, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, filp);
+	KUNIT_ASSERT_NOT_NULL(test, sock->sk);
+	sock->file = filp;
+
+	/* Act */
+	err = handshake_req_submit(sock, req1, GFP_KERNEL);
+	KUNIT_ASSERT_EQ(test, err, 0);
+	err = handshake_req_submit(sock, req2, GFP_KERNEL);
+
+	/* Assert */
+	KUNIT_EXPECT_EQ(test, err, -EBUSY);
+
+	handshake_req_cancel(sock->sk);
+	fput(filp);
+}
+
+static void handshake_req_cancel_test1(struct kunit *test)
+{
+	struct handshake_req *req;
+	struct socket *sock;
+	struct file *filp;
+	bool result;
+	int err;
+
+	/* Arrange */
+	req = handshake_req_alloc(&handshake_req_alloc_proto_good, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, req);
+
+	err = __sock_create(&init_net, PF_INET, SOCK_STREAM, IPPROTO_TCP,
+			    &sock, 1);
+	KUNIT_ASSERT_EQ(test, err, 0);
+
+	filp = sock_alloc_file(sock, O_NONBLOCK, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, filp);
+	sock->file = filp;
+
+	err = handshake_req_submit(sock, req, GFP_KERNEL);
+	KUNIT_ASSERT_EQ(test, err, 0);
+
+	/* NB: handshake_req hasn't been accepted */
+
+	/* Act */
+	result = handshake_req_cancel(sock->sk);
+
+	/* Assert */
+	KUNIT_EXPECT_TRUE(test, result);
+
+	fput(filp);
+}
+
+static void handshake_req_cancel_test2(struct kunit *test)
+{
+	struct handshake_req *req, *next;
+	struct handshake_net *hn;
+	struct socket *sock;
+	struct file *filp;
+	struct net *net;
+	bool result;
+	int err;
+
+	/* Arrange */
+	req = handshake_req_alloc(&handshake_req_alloc_proto_good, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, req);
+
+	err = __sock_create(&init_net, PF_INET, SOCK_STREAM, IPPROTO_TCP,
+			    &sock, 1);
+	KUNIT_ASSERT_EQ(test, err, 0);
+
+	filp = sock_alloc_file(sock, O_NONBLOCK, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, filp);
+	sock->file = filp;
+
+	err = handshake_req_submit(sock, req, GFP_KERNEL);
+	KUNIT_ASSERT_EQ(test, err, 0);
+
+	net = sock_net(sock->sk);
+	hn = handshake_pernet(net);
+	KUNIT_ASSERT_NOT_NULL(test, hn);
+
+	/* Pretend to accept this request */
+	next = handshake_req_next(hn, HANDSHAKE_HANDLER_CLASS_TLSHD);
+	KUNIT_ASSERT_PTR_EQ(test, req, next);
+
+	/* Act */
+	result = handshake_req_cancel(sock->sk);
+
+	/* Assert */
+	KUNIT_EXPECT_TRUE(test, result);
+
+	fput(filp);
+}
+
+static void handshake_req_cancel_test3(struct kunit *test)
+{
+	struct handshake_req *req, *next;
+	struct handshake_net *hn;
+	struct socket *sock;
+	struct file *filp;
+	struct net *net;
+	bool result;
+	int err;
+
+	/* Arrange */
+	req = handshake_req_alloc(&handshake_req_alloc_proto_good, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, req);
+
+	err = __sock_create(&init_net, PF_INET, SOCK_STREAM, IPPROTO_TCP,
+			    &sock, 1);
+	KUNIT_ASSERT_EQ(test, err, 0);
+
+	filp = sock_alloc_file(sock, O_NONBLOCK, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, filp);
+	sock->file = filp;
+
+	err = handshake_req_submit(sock, req, GFP_KERNEL);
+	KUNIT_ASSERT_EQ(test, err, 0);
+
+	net = sock_net(sock->sk);
+	hn = handshake_pernet(net);
+	KUNIT_ASSERT_NOT_NULL(test, hn);
+
+	/* Pretend to accept this request */
+	next = handshake_req_next(hn, HANDSHAKE_HANDLER_CLASS_TLSHD);
+	KUNIT_ASSERT_PTR_EQ(test, req, next);
+
+	/* Pretend to complete this request */
+	handshake_complete(next, -ETIMEDOUT, NULL);
+
+	/* Act */
+	result = handshake_req_cancel(sock->sk);
+
+	/* Assert */
+	KUNIT_EXPECT_FALSE(test, result);
+
+	fput(filp);
+}
+
+static struct handshake_req *handshake_req_destroy_test;
+
+static void test_destroy_func(struct handshake_req *req)
+{
+	handshake_req_destroy_test = req;
+}
+
+static struct handshake_proto handshake_req_alloc_proto_destroy = {
+	.hp_handler_class	= HANDSHAKE_HANDLER_CLASS_TLSHD,
+	.hp_accept		= test_accept_func,
+	.hp_done		= test_done_func,
+	.hp_destroy		= test_destroy_func,
+};
+
+static void handshake_req_destroy_test1(struct kunit *test)
+{
+	struct handshake_req *req;
+	struct socket *sock;
+	struct file *filp;
+	int err;
+
+	/* Arrange */
+	handshake_req_destroy_test = NULL;
+
+	req = handshake_req_alloc(&handshake_req_alloc_proto_destroy, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, req);
+
+	err = __sock_create(&init_net, PF_INET, SOCK_STREAM, IPPROTO_TCP,
+			    &sock, 1);
+	KUNIT_ASSERT_EQ(test, err, 0);
+
+	filp = sock_alloc_file(sock, O_NONBLOCK, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, filp);
+	sock->file = filp;
+
+	err = handshake_req_submit(sock, req, GFP_KERNEL);
+	KUNIT_ASSERT_EQ(test, err, 0);
+
+	handshake_req_cancel(sock->sk);
+
+	/* Act */
+	fput(filp);
+
+	/* Assert */
+	KUNIT_EXPECT_PTR_EQ(test, handshake_req_destroy_test, req);
+}
+
+static struct kunit_case handshake_api_test_cases[] = {
+	{
+		.name			= "req_alloc API fuzzing",
+		.run_case		= handshake_req_alloc_case,
+		.generate_params	= handshake_req_alloc_gen_params,
+	},
+	{
+		.name			= "req_submit NULL req arg",
+		.run_case		= handshake_req_submit_test1,
+	},
+	{
+		.name			= "req_submit NULL sock arg",
+		.run_case		= handshake_req_submit_test2,
+	},
+	{
+		.name			= "req_submit NULL sock->file",
+		.run_case		= handshake_req_submit_test3,
+	},
+	{
+		.name			= "req_lookup works",
+		.run_case		= handshake_req_submit_test4,
+	},
+	{
+		.name			= "req_submit max pending",
+		.run_case		= handshake_req_submit_test5,
+	},
+	{
+		.name			= "req_submit multiple",
+		.run_case		= handshake_req_submit_test6,
+	},
+	{
+		.name			= "req_cancel before accept",
+		.run_case		= handshake_req_cancel_test1,
+	},
+	{
+		.name			= "req_cancel after accept",
+		.run_case		= handshake_req_cancel_test2,
+	},
+	{
+		.name			= "req_cancel after done",
+		.run_case		= handshake_req_cancel_test3,
+	},
+	{
+		.name			= "req_destroy works",
+		.run_case		= handshake_req_destroy_test1,
+	},
+	{}
+};
+
+static struct kunit_suite handshake_api_suite = {
+       .name                   = "Handshake API tests",
+       .test_cases             = handshake_api_test_cases,
+};
+
+kunit_test_suites(&handshake_api_suite);
+
+MODULE_DESCRIPTION("Test handshake upcall API functions");
+MODULE_LICENSE("GPL");
diff --git a/net/handshake/handshake.h b/net/handshake/handshake.h
new file mode 100644
index 000000000..a48163765
--- /dev/null
+++ b/net/handshake/handshake.h
@@ -0,0 +1,93 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Generic netlink handshake service
+ *
+ * Author: Chuck Lever <chuck.lever@oracle.com>
+ *
+ * Copyright (c) 2023, Oracle and/or its affiliates.
+ */
+
+#ifndef _INTERNAL_HANDSHAKE_H
+#define _INTERNAL_HANDSHAKE_H
+
+/* Per-net namespace context */
+struct handshake_net {
+	spinlock_t		hn_lock;	/* protects next 3 fields */
+	int			hn_pending;
+	int			hn_pending_max;
+	struct list_head	hn_requests;
+
+	unsigned long		hn_flags;
+};
+
+enum hn_flags_bits {
+	HANDSHAKE_F_NET_DRAINING,
+};
+
+struct handshake_proto;
+
+/* One handshake request */
+struct handshake_req {
+	struct list_head		hr_list;
+	struct rhash_head		hr_rhash;
+	unsigned long			hr_flags;
+	const struct handshake_proto	*hr_proto;
+	struct sock			*hr_sk;
+	void				(*hr_odestruct)(struct sock *sk);
+
+	/* Always the last field */
+	char				hr_priv[];
+};
+
+enum hr_flags_bits {
+	HANDSHAKE_F_REQ_COMPLETED,
+	HANDSHAKE_F_REQ_SESSION,
+};
+
+struct genl_info;
+
+/* Invariants for all handshake requests for one transport layer
+ * security protocol
+ */
+struct handshake_proto {
+	int			hp_handler_class;
+	size_t			hp_privsize;
+	unsigned long		hp_flags;
+
+	int			(*hp_accept)(struct handshake_req *req,
+					     struct genl_info *info, int fd);
+	void			(*hp_done)(struct handshake_req *req,
+					   unsigned int status,
+					   struct genl_info *info);
+	void			(*hp_destroy)(struct handshake_req *req);
+};
+
+enum hp_flags_bits {
+	HANDSHAKE_F_PROTO_NOTIFY,
+};
+
+/* alert.c */
+int tls_alert_send(struct socket *sock, u8 level, u8 description);
+
+/* netlink.c */
+int handshake_genl_notify(struct net *net, const struct handshake_proto *proto,
+			  gfp_t flags);
+struct nlmsghdr *handshake_genl_put(struct sk_buff *msg,
+				    struct genl_info *info);
+struct handshake_net *handshake_pernet(struct net *net);
+
+/* request.c */
+struct handshake_req *handshake_req_alloc(const struct handshake_proto *proto,
+					  gfp_t flags);
+int handshake_req_hash_init(void);
+void handshake_req_hash_destroy(void);
+void *handshake_req_private(struct handshake_req *req);
+struct handshake_req *handshake_req_hash_lookup(struct sock *sk);
+struct handshake_req *handshake_req_next(struct handshake_net *hn, int class);
+int handshake_req_submit(struct socket *sock, struct handshake_req *req,
+			 gfp_t flags);
+void handshake_complete(struct handshake_req *req, unsigned int status,
+			struct genl_info *info);
+bool handshake_req_cancel(struct sock *sk);
+
+#endif /* _INTERNAL_HANDSHAKE_H */
diff --git a/net/handshake/netlink.c b/net/handshake/netlink.c
new file mode 100644
index 000000000..80c730269
--- /dev/null
+++ b/net/handshake/netlink.c
@@ -0,0 +1,291 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Generic netlink handshake service
+ *
+ * Author: Chuck Lever <chuck.lever@oracle.com>
+ *
+ * Copyright (c) 2023, Oracle and/or its affiliates.
+ */
+
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/mm.h>
+
+#include <net/sock.h>
+#include <net/genetlink.h>
+#include <net/netns/generic.h>
+
+#include <kunit/visibility.h>
+
+#include <uapi/linux/handshake.h>
+#include "handshake.h"
+#include "genl.h"
+
+#include <trace/events/handshake.h>
+
+/**
+ * handshake_genl_notify - Notify handlers that a request is waiting
+ * @net: target network namespace
+ * @proto: handshake protocol
+ * @flags: memory allocation control flags
+ *
+ * Returns zero on success or a negative errno if notification failed.
+ */
+int handshake_genl_notify(struct net *net, const struct handshake_proto *proto,
+			  gfp_t flags)
+{
+	struct sk_buff *msg;
+	void *hdr;
+
+	/* Disable notifications during unit testing */
+	if (!test_bit(HANDSHAKE_F_PROTO_NOTIFY, &proto->hp_flags))
+		return 0;
+
+	if (!genl_has_listeners(&handshake_nl_family, net,
+				proto->hp_handler_class))
+		return -ESRCH;
+
+	msg = genlmsg_new(GENLMSG_DEFAULT_SIZE, flags);
+	if (!msg)
+		return -ENOMEM;
+
+	hdr = genlmsg_put(msg, 0, 0, &handshake_nl_family, 0,
+			  HANDSHAKE_CMD_READY);
+	if (!hdr)
+		goto out_free;
+
+	if (nla_put_u32(msg, HANDSHAKE_A_ACCEPT_HANDLER_CLASS,
+			proto->hp_handler_class) < 0) {
+		genlmsg_cancel(msg, hdr);
+		goto out_free;
+	}
+
+	genlmsg_end(msg, hdr);
+	return genlmsg_multicast_netns(&handshake_nl_family, net, msg,
+				       0, proto->hp_handler_class, flags);
+
+out_free:
+	nlmsg_free(msg);
+	return -EMSGSIZE;
+}
+
+/**
+ * handshake_genl_put - Create a generic netlink message header
+ * @msg: buffer in which to create the header
+ * @info: generic netlink message context
+ *
+ * Returns a ready-to-use header, or NULL.
+ */
+struct nlmsghdr *handshake_genl_put(struct sk_buff *msg,
+				    struct genl_info *info)
+{
+	return genlmsg_put(msg, info->snd_portid, info->snd_seq,
+			   &handshake_nl_family, 0, info->genlhdr->cmd);
+}
+EXPORT_SYMBOL(handshake_genl_put);
+
+int handshake_nl_accept_doit(struct sk_buff *skb, struct genl_info *info)
+{
+	struct net *net = sock_net(skb->sk);
+	struct handshake_net *hn = handshake_pernet(net);
+	struct handshake_req *req = NULL;
+	struct socket *sock;
+	int class, fd, err;
+
+	err = -EOPNOTSUPP;
+	if (!hn)
+		goto out_status;
+
+	err = -EINVAL;
+	if (GENL_REQ_ATTR_CHECK(info, HANDSHAKE_A_ACCEPT_HANDLER_CLASS))
+		goto out_status;
+	class = nla_get_u32(info->attrs[HANDSHAKE_A_ACCEPT_HANDLER_CLASS]);
+
+	err = -EAGAIN;
+	req = handshake_req_next(hn, class);
+	if (!req)
+		goto out_status;
+
+	sock = req->hr_sk->sk_socket;
+	fd = get_unused_fd_flags(O_CLOEXEC);
+	if (fd < 0) {
+		err = fd;
+		goto out_complete;
+	}
+
+	err = req->hr_proto->hp_accept(req, info, fd);
+	if (err) {
+		put_unused_fd(fd);
+		goto out_complete;
+	}
+
+	fd_install(fd, get_file(sock->file));
+
+	trace_handshake_cmd_accept(net, req, req->hr_sk, fd);
+	return 0;
+
+out_complete:
+	handshake_complete(req, -EIO, NULL);
+out_status:
+	trace_handshake_cmd_accept_err(net, req, NULL, err);
+	return err;
+}
+
+int handshake_nl_done_doit(struct sk_buff *skb, struct genl_info *info)
+{
+	struct net *net = sock_net(skb->sk);
+	struct handshake_req *req;
+	struct socket *sock;
+	int fd, status, err;
+
+	if (GENL_REQ_ATTR_CHECK(info, HANDSHAKE_A_DONE_SOCKFD))
+		return -EINVAL;
+	fd = nla_get_u32(info->attrs[HANDSHAKE_A_DONE_SOCKFD]);
+
+	sock = sockfd_lookup(fd, &err);
+	if (!sock)
+		return err;
+
+	req = handshake_req_hash_lookup(sock->sk);
+	if (!req) {
+		err = -EBUSY;
+		trace_handshake_cmd_done_err(net, req, sock->sk, err);
+		fput(sock->file);
+		return err;
+	}
+
+	trace_handshake_cmd_done(net, req, sock->sk, fd);
+
+	status = -EIO;
+	if (info->attrs[HANDSHAKE_A_DONE_STATUS])
+		status = nla_get_u32(info->attrs[HANDSHAKE_A_DONE_STATUS]);
+
+	handshake_complete(req, status, info);
+	fput(sock->file);
+	return 0;
+}
+
+static unsigned int handshake_net_id;
+
+static int __net_init handshake_net_init(struct net *net)
+{
+	struct handshake_net *hn = net_generic(net, handshake_net_id);
+	unsigned long tmp;
+	struct sysinfo si;
+
+	/*
+	 * Arbitrary limit to prevent handshakes that do not make
+	 * progress from clogging up the system. The cap scales up
+	 * with the amount of physical memory on the system.
+	 */
+	si_meminfo(&si);
+	tmp = si.totalram / (25 * si.mem_unit);
+	hn->hn_pending_max = clamp(tmp, 3UL, 50UL);
+
+	spin_lock_init(&hn->hn_lock);
+	hn->hn_pending = 0;
+	hn->hn_flags = 0;
+	INIT_LIST_HEAD(&hn->hn_requests);
+	return 0;
+}
+
+static void __net_exit handshake_net_exit(struct net *net)
+{
+	struct handshake_net *hn = net_generic(net, handshake_net_id);
+	struct handshake_req *req;
+	LIST_HEAD(requests);
+
+	/*
+	 * Drain the net's pending list. Requests that have been
+	 * accepted and are in progress will be destroyed when
+	 * the socket is closed.
+	 */
+	spin_lock(&hn->hn_lock);
+	set_bit(HANDSHAKE_F_NET_DRAINING, &hn->hn_flags);
+	list_splice_init(&requests, &hn->hn_requests);
+	spin_unlock(&hn->hn_lock);
+
+	while (!list_empty(&requests)) {
+		req = list_first_entry(&requests, struct handshake_req, hr_list);
+		list_del(&req->hr_list);
+
+		/*
+		 * Requests on this list have not yet been
+		 * accepted, so they do not have an fd to put.
+		 */
+
+		handshake_complete(req, -ETIMEDOUT, NULL);
+	}
+}
+
+static struct pernet_operations handshake_genl_net_ops = {
+	.init		= handshake_net_init,
+	.exit		= handshake_net_exit,
+	.id		= &handshake_net_id,
+	.size		= sizeof(struct handshake_net),
+};
+
+/**
+ * handshake_pernet - Get the handshake private per-net structure
+ * @net: network namespace
+ *
+ * Returns a pointer to the net's private per-net structure for the
+ * handshake module, or NULL if handshake_init() failed.
+ */
+struct handshake_net *handshake_pernet(struct net *net)
+{
+	return handshake_net_id ?
+		net_generic(net, handshake_net_id) : NULL;
+}
+EXPORT_SYMBOL_IF_KUNIT(handshake_pernet);
+
+static int __init handshake_init(void)
+{
+	int ret;
+
+	ret = handshake_req_hash_init();
+	if (ret) {
+		pr_warn("handshake: hash initialization failed (%d)\n", ret);
+		return ret;
+	}
+
+	ret = genl_register_family(&handshake_nl_family);
+	if (ret) {
+		pr_warn("handshake: netlink registration failed (%d)\n", ret);
+		handshake_req_hash_destroy();
+		return ret;
+	}
+
+	/*
+	 * ORDER: register_pernet_subsys must be done last.
+	 *
+	 *	If initialization does not make it past pernet_subsys
+	 *	registration, then handshake_net_id will remain 0. That
+	 *	shunts the handshake consumer API to return ENOTSUPP
+	 *	to prevent it from dereferencing something that hasn't
+	 *	been allocated.
+	 */
+	ret = register_pernet_subsys(&handshake_genl_net_ops);
+	if (ret) {
+		pr_warn("handshake: pernet registration failed (%d)\n", ret);
+		genl_unregister_family(&handshake_nl_family);
+		handshake_req_hash_destroy();
+	}
+
+	return ret;
+}
+
+static void __exit handshake_exit(void)
+{
+	unregister_pernet_subsys(&handshake_genl_net_ops);
+	handshake_net_id = 0;
+
+	handshake_req_hash_destroy();
+	genl_unregister_family(&handshake_nl_family);
+}
+
+module_init(handshake_init);
+module_exit(handshake_exit);
diff --git a/net/handshake/request.c b/net/handshake/request.c
new file mode 100644
index 000000000..94d5cef3e
--- /dev/null
+++ b/net/handshake/request.c
@@ -0,0 +1,344 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Handshake request lifetime events
+ *
+ * Author: Chuck Lever <chuck.lever@oracle.com>
+ *
+ * Copyright (c) 2023, Oracle and/or its affiliates.
+ */
+
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/inet.h>
+#include <linux/fdtable.h>
+#include <linux/rhashtable.h>
+
+#include <net/sock.h>
+#include <net/genetlink.h>
+#include <net/netns/generic.h>
+
+#include <kunit/visibility.h>
+
+#include <uapi/linux/handshake.h>
+#include "handshake.h"
+
+#include <trace/events/handshake.h>
+
+/*
+ * We need both a handshake_req -> sock mapping, and a sock ->
+ * handshake_req mapping. Both are one-to-one.
+ *
+ * To avoid adding another pointer field to struct sock, net/handshake
+ * maintains a hash table, indexed by the memory address of @sock, to
+ * find the struct handshake_req outstanding for that socket. The
+ * reverse direction uses a simple pointer field in the handshake_req
+ * struct.
+ */
+
+static struct rhashtable handshake_rhashtbl ____cacheline_aligned_in_smp;
+
+static const struct rhashtable_params handshake_rhash_params = {
+	.key_len		= sizeof_field(struct handshake_req, hr_sk),
+	.key_offset		= offsetof(struct handshake_req, hr_sk),
+	.head_offset		= offsetof(struct handshake_req, hr_rhash),
+	.automatic_shrinking	= true,
+};
+
+int handshake_req_hash_init(void)
+{
+	return rhashtable_init(&handshake_rhashtbl, &handshake_rhash_params);
+}
+
+void handshake_req_hash_destroy(void)
+{
+	rhashtable_destroy(&handshake_rhashtbl);
+}
+
+struct handshake_req *handshake_req_hash_lookup(struct sock *sk)
+{
+	return rhashtable_lookup_fast(&handshake_rhashtbl, &sk,
+				      handshake_rhash_params);
+}
+EXPORT_SYMBOL_IF_KUNIT(handshake_req_hash_lookup);
+
+static bool handshake_req_hash_add(struct handshake_req *req)
+{
+	int ret;
+
+	ret = rhashtable_lookup_insert_fast(&handshake_rhashtbl,
+					    &req->hr_rhash,
+					    handshake_rhash_params);
+	return ret == 0;
+}
+
+static void handshake_req_destroy(struct handshake_req *req)
+{
+	if (req->hr_proto->hp_destroy)
+		req->hr_proto->hp_destroy(req);
+	rhashtable_remove_fast(&handshake_rhashtbl, &req->hr_rhash,
+			       handshake_rhash_params);
+	kfree(req);
+}
+
+static void handshake_sk_destruct(struct sock *sk)
+{
+	void (*sk_destruct)(struct sock *sk);
+	struct handshake_req *req;
+
+	req = handshake_req_hash_lookup(sk);
+	if (!req)
+		return;
+
+	trace_handshake_destruct(sock_net(sk), req, sk);
+	sk_destruct = req->hr_odestruct;
+	handshake_req_destroy(req);
+	if (sk_destruct)
+		sk_destruct(sk);
+}
+
+/**
+ * handshake_req_alloc - Allocate a handshake request
+ * @proto: security protocol
+ * @flags: memory allocation flags
+ *
+ * Returns an initialized handshake_req or NULL.
+ */
+struct handshake_req *handshake_req_alloc(const struct handshake_proto *proto,
+					  gfp_t flags)
+{
+	struct handshake_req *req;
+
+	if (!proto)
+		return NULL;
+	if (proto->hp_handler_class <= HANDSHAKE_HANDLER_CLASS_NONE)
+		return NULL;
+	if (proto->hp_handler_class >= HANDSHAKE_HANDLER_CLASS_MAX)
+		return NULL;
+	if (!proto->hp_accept || !proto->hp_done)
+		return NULL;
+
+	req = kzalloc(struct_size(req, hr_priv, proto->hp_privsize), flags);
+	if (!req)
+		return NULL;
+
+	INIT_LIST_HEAD(&req->hr_list);
+	req->hr_proto = proto;
+	return req;
+}
+EXPORT_SYMBOL(handshake_req_alloc);
+
+/**
+ * handshake_req_private - Get per-handshake private data
+ * @req: handshake arguments
+ *
+ */
+void *handshake_req_private(struct handshake_req *req)
+{
+	return (void *)&req->hr_priv;
+}
+EXPORT_SYMBOL(handshake_req_private);
+
+static bool __add_pending_locked(struct handshake_net *hn,
+				 struct handshake_req *req)
+{
+	if (WARN_ON_ONCE(!list_empty(&req->hr_list)))
+		return false;
+	hn->hn_pending++;
+	list_add_tail(&req->hr_list, &hn->hn_requests);
+	return true;
+}
+
+static void __remove_pending_locked(struct handshake_net *hn,
+				    struct handshake_req *req)
+{
+	hn->hn_pending--;
+	list_del_init(&req->hr_list);
+}
+
+/*
+ * Returns %true if the request was found on @net's pending list,
+ * otherwise %false.
+ *
+ * If @req was on a pending list, it has not yet been accepted.
+ */
+static bool remove_pending(struct handshake_net *hn, struct handshake_req *req)
+{
+	bool ret = false;
+
+	spin_lock(&hn->hn_lock);
+	if (!list_empty(&req->hr_list)) {
+		__remove_pending_locked(hn, req);
+		ret = true;
+	}
+	spin_unlock(&hn->hn_lock);
+
+	return ret;
+}
+
+struct handshake_req *handshake_req_next(struct handshake_net *hn, int class)
+{
+	struct handshake_req *req, *pos;
+
+	req = NULL;
+	spin_lock(&hn->hn_lock);
+	list_for_each_entry(pos, &hn->hn_requests, hr_list) {
+		if (pos->hr_proto->hp_handler_class != class)
+			continue;
+		__remove_pending_locked(hn, pos);
+		req = pos;
+		break;
+	}
+	spin_unlock(&hn->hn_lock);
+
+	return req;
+}
+EXPORT_SYMBOL_IF_KUNIT(handshake_req_next);
+
+/**
+ * handshake_req_submit - Submit a handshake request
+ * @sock: open socket on which to perform the handshake
+ * @req: handshake arguments
+ * @flags: memory allocation flags
+ *
+ * Return values:
+ *   %0: Request queued
+ *   %-EINVAL: Invalid argument
+ *   %-EBUSY: A handshake is already under way for this socket
+ *   %-ESRCH: No handshake agent is available
+ *   %-EAGAIN: Too many pending handshake requests
+ *   %-ENOMEM: Failed to allocate memory
+ *   %-EMSGSIZE: Failed to construct notification message
+ *   %-EOPNOTSUPP: Handshake module not initialized
+ *
+ * A zero return value from handshake_req_submit() means that
+ * exactly one subsequent completion callback is guaranteed.
+ *
+ * A negative return value from handshake_req_submit() means that
+ * no completion callback will be done and that @req has been
+ * destroyed.
+ */
+int handshake_req_submit(struct socket *sock, struct handshake_req *req,
+			 gfp_t flags)
+{
+	struct handshake_net *hn;
+	struct net *net;
+	int ret;
+
+	if (!sock || !req || !sock->file) {
+		kfree(req);
+		return -EINVAL;
+	}
+
+	req->hr_sk = sock->sk;
+	if (!req->hr_sk) {
+		kfree(req);
+		return -EINVAL;
+	}
+	req->hr_odestruct = req->hr_sk->sk_destruct;
+	req->hr_sk->sk_destruct = handshake_sk_destruct;
+
+	ret = -EOPNOTSUPP;
+	net = sock_net(req->hr_sk);
+	hn = handshake_pernet(net);
+	if (!hn)
+		goto out_err;
+
+	ret = -EAGAIN;
+	if (READ_ONCE(hn->hn_pending) >= hn->hn_pending_max)
+		goto out_err;
+
+	spin_lock(&hn->hn_lock);
+	ret = -EOPNOTSUPP;
+	if (test_bit(HANDSHAKE_F_NET_DRAINING, &hn->hn_flags))
+		goto out_unlock;
+	ret = -EBUSY;
+	if (!handshake_req_hash_add(req))
+		goto out_unlock;
+	if (!__add_pending_locked(hn, req))
+		goto out_unlock;
+	spin_unlock(&hn->hn_lock);
+
+	ret = handshake_genl_notify(net, req->hr_proto, flags);
+	if (ret) {
+		trace_handshake_notify_err(net, req, req->hr_sk, ret);
+		if (remove_pending(hn, req))
+			goto out_err;
+	}
+
+	/* Prevent socket release while a handshake request is pending */
+	sock_hold(req->hr_sk);
+
+	trace_handshake_submit(net, req, req->hr_sk);
+	return 0;
+
+out_unlock:
+	spin_unlock(&hn->hn_lock);
+out_err:
+	trace_handshake_submit_err(net, req, req->hr_sk, ret);
+	handshake_req_destroy(req);
+	return ret;
+}
+EXPORT_SYMBOL(handshake_req_submit);
+
+void handshake_complete(struct handshake_req *req, unsigned int status,
+			struct genl_info *info)
+{
+	struct sock *sk = req->hr_sk;
+	struct net *net = sock_net(sk);
+
+	if (!test_and_set_bit(HANDSHAKE_F_REQ_COMPLETED, &req->hr_flags)) {
+		trace_handshake_complete(net, req, sk, status);
+		req->hr_proto->hp_done(req, status, info);
+
+		/* Handshake request is no longer pending */
+		sock_put(sk);
+	}
+}
+EXPORT_SYMBOL_IF_KUNIT(handshake_complete);
+
+/**
+ * handshake_req_cancel - Cancel an in-progress handshake
+ * @sk: socket on which there is an ongoing handshake
+ *
+ * Request cancellation races with request completion. To determine
+ * who won, callers examine the return value from this function.
+ *
+ * Return values:
+ *   %true - Uncompleted handshake request was canceled
+ *   %false - Handshake request already completed or not found
+ */
+bool handshake_req_cancel(struct sock *sk)
+{
+	struct handshake_req *req;
+	struct handshake_net *hn;
+	struct net *net;
+
+	net = sock_net(sk);
+	req = handshake_req_hash_lookup(sk);
+	if (!req) {
+		trace_handshake_cancel_none(net, req, sk);
+		return false;
+	}
+
+	hn = handshake_pernet(net);
+	if (hn && remove_pending(hn, req)) {
+		/* Request hadn't been accepted */
+		goto out_true;
+	}
+	if (test_and_set_bit(HANDSHAKE_F_REQ_COMPLETED, &req->hr_flags)) {
+		/* Request already completed */
+		trace_handshake_cancel_busy(net, req, sk);
+		return false;
+	}
+
+out_true:
+	trace_handshake_cancel(net, req, sk);
+
+	/* Handshake request is no longer pending */
+	sock_put(sk);
+	return true;
+}
+EXPORT_SYMBOL(handshake_req_cancel);
diff --git a/net/handshake/tlshd.c b/net/handshake/tlshd.c
new file mode 100644
index 000000000..bbfb4095d
--- /dev/null
+++ b/net/handshake/tlshd.c
@@ -0,0 +1,449 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Establish a TLS session for a kernel socket consumer
+ * using the tlshd user space handler.
+ *
+ * Author: Chuck Lever <chuck.lever@oracle.com>
+ *
+ * Copyright (c) 2021-2023, Oracle and/or its affiliates.
+ */
+
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/key.h>
+
+#include <net/sock.h>
+#include <net/handshake.h>
+#include <net/genetlink.h>
+#include <net/tls_prot.h>
+
+#include <uapi/linux/keyctl.h>
+#include <uapi/linux/handshake.h>
+#include "handshake.h"
+
+struct tls_handshake_req {
+	void			(*th_consumer_done)(void *data, int status,
+						    key_serial_t peerid);
+	void			*th_consumer_data;
+
+	int			th_type;
+	unsigned int		th_timeout_ms;
+	int			th_auth_mode;
+	const char		*th_peername;
+	key_serial_t		th_keyring;
+	key_serial_t		th_certificate;
+	key_serial_t		th_privkey;
+
+	unsigned int		th_num_peerids;
+	key_serial_t		th_peerid[5];
+};
+
+static struct tls_handshake_req *
+tls_handshake_req_init(struct handshake_req *req,
+		       const struct tls_handshake_args *args)
+{
+	struct tls_handshake_req *treq = handshake_req_private(req);
+
+	treq->th_timeout_ms = args->ta_timeout_ms;
+	treq->th_consumer_done = args->ta_done;
+	treq->th_consumer_data = args->ta_data;
+	treq->th_peername = args->ta_peername;
+	treq->th_keyring = args->ta_keyring;
+	treq->th_num_peerids = 0;
+	treq->th_certificate = TLS_NO_CERT;
+	treq->th_privkey = TLS_NO_PRIVKEY;
+	return treq;
+}
+
+static void tls_handshake_remote_peerids(struct tls_handshake_req *treq,
+					 struct genl_info *info)
+{
+	struct nlattr *head = nlmsg_attrdata(info->nlhdr, GENL_HDRLEN);
+	int rem, len = nlmsg_attrlen(info->nlhdr, GENL_HDRLEN);
+	struct nlattr *nla;
+	unsigned int i;
+
+	i = 0;
+	nla_for_each_attr(nla, head, len, rem) {
+		if (nla_type(nla) == HANDSHAKE_A_DONE_REMOTE_AUTH)
+			i++;
+	}
+	if (!i)
+		return;
+	treq->th_num_peerids = min_t(unsigned int, i,
+				     ARRAY_SIZE(treq->th_peerid));
+
+	i = 0;
+	nla_for_each_attr(nla, head, len, rem) {
+		if (nla_type(nla) == HANDSHAKE_A_DONE_REMOTE_AUTH)
+			treq->th_peerid[i++] = nla_get_u32(nla);
+		if (i >= treq->th_num_peerids)
+			break;
+	}
+}
+
+/**
+ * tls_handshake_done - callback to handle a CMD_DONE request
+ * @req: socket on which the handshake was performed
+ * @status: session status code
+ * @info: full results of session establishment
+ *
+ */
+static void tls_handshake_done(struct handshake_req *req,
+			       unsigned int status, struct genl_info *info)
+{
+	struct tls_handshake_req *treq = handshake_req_private(req);
+
+	treq->th_peerid[0] = TLS_NO_PEERID;
+	if (info)
+		tls_handshake_remote_peerids(treq, info);
+
+	if (!status)
+		set_bit(HANDSHAKE_F_REQ_SESSION, &req->hr_flags);
+
+	treq->th_consumer_done(treq->th_consumer_data, -status,
+			       treq->th_peerid[0]);
+}
+
+#if IS_ENABLED(CONFIG_KEYS)
+static int tls_handshake_private_keyring(struct tls_handshake_req *treq)
+{
+	key_ref_t process_keyring_ref, keyring_ref;
+	int ret;
+
+	if (treq->th_keyring == TLS_NO_KEYRING)
+		return 0;
+
+	process_keyring_ref = lookup_user_key(KEY_SPEC_PROCESS_KEYRING,
+					      KEY_LOOKUP_CREATE,
+					      KEY_NEED_WRITE);
+	if (IS_ERR(process_keyring_ref)) {
+		ret = PTR_ERR(process_keyring_ref);
+		goto out;
+	}
+
+	keyring_ref = lookup_user_key(treq->th_keyring, KEY_LOOKUP_CREATE,
+				      KEY_NEED_LINK);
+	if (IS_ERR(keyring_ref)) {
+		ret = PTR_ERR(keyring_ref);
+		goto out_put_key;
+	}
+
+	ret = key_link(key_ref_to_ptr(process_keyring_ref),
+		       key_ref_to_ptr(keyring_ref));
+
+	key_ref_put(keyring_ref);
+out_put_key:
+	key_ref_put(process_keyring_ref);
+out:
+	return ret;
+}
+#else
+static int tls_handshake_private_keyring(struct tls_handshake_req *treq)
+{
+	return 0;
+}
+#endif
+
+static int tls_handshake_put_peer_identity(struct sk_buff *msg,
+					   struct tls_handshake_req *treq)
+{
+	unsigned int i;
+
+	for (i = 0; i < treq->th_num_peerids; i++)
+		if (nla_put_u32(msg, HANDSHAKE_A_ACCEPT_PEER_IDENTITY,
+				treq->th_peerid[i]) < 0)
+			return -EMSGSIZE;
+	return 0;
+}
+
+static int tls_handshake_put_certificate(struct sk_buff *msg,
+					 struct tls_handshake_req *treq)
+{
+	struct nlattr *entry_attr;
+
+	if (treq->th_certificate == TLS_NO_CERT &&
+	    treq->th_privkey == TLS_NO_PRIVKEY)
+		return 0;
+
+	entry_attr = nla_nest_start(msg, HANDSHAKE_A_ACCEPT_CERTIFICATE);
+	if (!entry_attr)
+		return -EMSGSIZE;
+
+	if (nla_put_u32(msg, HANDSHAKE_A_X509_CERT,
+			treq->th_certificate) ||
+	    nla_put_u32(msg, HANDSHAKE_A_X509_PRIVKEY,
+			treq->th_privkey)) {
+		nla_nest_cancel(msg, entry_attr);
+		return -EMSGSIZE;
+	}
+
+	nla_nest_end(msg, entry_attr);
+	return 0;
+}
+
+/**
+ * tls_handshake_accept - callback to construct a CMD_ACCEPT response
+ * @req: handshake parameters to return
+ * @info: generic netlink message context
+ * @fd: file descriptor to be returned
+ *
+ * Returns zero on success, or a negative errno on failure.
+ */
+static int tls_handshake_accept(struct handshake_req *req,
+				struct genl_info *info, int fd)
+{
+	struct tls_handshake_req *treq = handshake_req_private(req);
+	struct nlmsghdr *hdr;
+	struct sk_buff *msg;
+	int ret;
+
+	ret = tls_handshake_private_keyring(treq);
+	if (ret < 0)
+		goto out;
+
+	ret = -ENOMEM;
+	msg = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		goto out;
+	hdr = handshake_genl_put(msg, info);
+	if (!hdr)
+		goto out_cancel;
+
+	ret = -EMSGSIZE;
+	ret = nla_put_u32(msg, HANDSHAKE_A_ACCEPT_SOCKFD, fd);
+	if (ret < 0)
+		goto out_cancel;
+	ret = nla_put_u32(msg, HANDSHAKE_A_ACCEPT_MESSAGE_TYPE, treq->th_type);
+	if (ret < 0)
+		goto out_cancel;
+	if (treq->th_peername) {
+		ret = nla_put_string(msg, HANDSHAKE_A_ACCEPT_PEERNAME,
+				     treq->th_peername);
+		if (ret < 0)
+			goto out_cancel;
+	}
+	if (treq->th_timeout_ms) {
+		ret = nla_put_u32(msg, HANDSHAKE_A_ACCEPT_TIMEOUT, treq->th_timeout_ms);
+		if (ret < 0)
+			goto out_cancel;
+	}
+
+	ret = nla_put_u32(msg, HANDSHAKE_A_ACCEPT_AUTH_MODE,
+			  treq->th_auth_mode);
+	if (ret < 0)
+		goto out_cancel;
+	switch (treq->th_auth_mode) {
+	case HANDSHAKE_AUTH_PSK:
+		ret = tls_handshake_put_peer_identity(msg, treq);
+		if (ret < 0)
+			goto out_cancel;
+		break;
+	case HANDSHAKE_AUTH_X509:
+		ret = tls_handshake_put_certificate(msg, treq);
+		if (ret < 0)
+			goto out_cancel;
+		break;
+	}
+
+	genlmsg_end(msg, hdr);
+	return genlmsg_reply(msg, info);
+
+out_cancel:
+	genlmsg_cancel(msg, hdr);
+out:
+	return ret;
+}
+
+static const struct handshake_proto tls_handshake_proto = {
+	.hp_handler_class	= HANDSHAKE_HANDLER_CLASS_TLSHD,
+	.hp_privsize		= sizeof(struct tls_handshake_req),
+	.hp_flags		= BIT(HANDSHAKE_F_PROTO_NOTIFY),
+
+	.hp_accept		= tls_handshake_accept,
+	.hp_done		= tls_handshake_done,
+};
+
+/**
+ * tls_client_hello_anon - request an anonymous TLS handshake on a socket
+ * @args: socket and handshake parameters for this request
+ * @flags: memory allocation control flags
+ *
+ * Return values:
+ *   %0: Handshake request enqueue; ->done will be called when complete
+ *   %-ESRCH: No user agent is available
+ *   %-ENOMEM: Memory allocation failed
+ */
+int tls_client_hello_anon(const struct tls_handshake_args *args, gfp_t flags)
+{
+	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_CLIENTHELLO;
+	treq->th_auth_mode = HANDSHAKE_AUTH_UNAUTH;
+
+	return handshake_req_submit(args->ta_sock, req, flags);
+}
+EXPORT_SYMBOL(tls_client_hello_anon);
+
+/**
+ * tls_client_hello_x509 - request an x.509-based TLS handshake on a socket
+ * @args: socket and handshake parameters for this request
+ * @flags: memory allocation control flags
+ *
+ * Return values:
+ *   %0: Handshake request enqueue; ->done will be called when complete
+ *   %-ESRCH: No user agent is available
+ *   %-ENOMEM: Memory allocation failed
+ */
+int tls_client_hello_x509(const struct tls_handshake_args *args, gfp_t flags)
+{
+	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_CLIENTHELLO;
+	treq->th_auth_mode = HANDSHAKE_AUTH_X509;
+	treq->th_certificate = args->ta_my_cert;
+	treq->th_privkey = args->ta_my_privkey;
+
+	return handshake_req_submit(args->ta_sock, req, flags);
+}
+EXPORT_SYMBOL(tls_client_hello_x509);
+
+/**
+ * tls_client_hello_psk - request a PSK-based TLS handshake on a socket
+ * @args: socket and handshake parameters for this request
+ * @flags: memory allocation control flags
+ *
+ * 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_hello_psk(const struct tls_handshake_args *args, gfp_t flags)
+{
+	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_CLIENTHELLO;
+	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_hello_psk);
+
+/**
+ * tls_server_hello_x509 - request a server TLS handshake on a socket
+ * @args: socket and handshake parameters for this request
+ * @flags: memory allocation control flags
+ *
+ * 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_hello_x509(const struct tls_handshake_args *args, gfp_t flags)
+{
+	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_SERVERHELLO;
+	treq->th_auth_mode = HANDSHAKE_AUTH_X509;
+	treq->th_certificate = args->ta_my_cert;
+	treq->th_privkey = args->ta_my_privkey;
+
+	return handshake_req_submit(args->ta_sock, req, flags);
+}
+EXPORT_SYMBOL(tls_server_hello_x509);
+
+/**
+ * tls_server_hello_psk - request a server TLS handshake on a socket
+ * @args: socket and handshake parameters for this request
+ * @flags: memory allocation control flags
+ *
+ * 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_hello_psk(const struct tls_handshake_args *args, gfp_t flags)
+{
+	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_SERVERHELLO;
+	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_hello_psk);
+
+/**
+ * tls_handshake_cancel - cancel a pending handshake
+ * @sk: socket on which there is an ongoing handshake
+ *
+ * Request cancellation races with request completion. To determine
+ * who won, callers examine the return value from this function.
+ *
+ * Return values:
+ *   %true - Uncompleted handshake request was canceled
+ *   %false - Handshake request already completed or not found
+ */
+bool tls_handshake_cancel(struct sock *sk)
+{
+	return handshake_req_cancel(sk);
+}
+EXPORT_SYMBOL(tls_handshake_cancel);
+
+/**
+ * tls_handshake_close - send a Closure alert
+ * @sock: an open socket
+ *
+ */
+void tls_handshake_close(struct socket *sock)
+{
+	struct handshake_req *req;
+
+	req = handshake_req_hash_lookup(sock->sk);
+	if (!req)
+		return;
+	if (!test_and_clear_bit(HANDSHAKE_F_REQ_SESSION, &req->hr_flags))
+		return;
+	tls_alert_send(sock, TLS_ALERT_LEVEL_WARNING,
+		       TLS_ALERT_DESC_CLOSE_NOTIFY);
+}
+EXPORT_SYMBOL(tls_handshake_close);
diff --git a/net/handshake/trace.c b/net/handshake/trace.c
new file mode 100644
index 000000000..44432d085
--- /dev/null
+++ b/net/handshake/trace.c
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Trace points for transport security layer handshakes.
+ *
+ * Author: Chuck Lever <chuck.lever@oracle.com>
+ *
+ * Copyright (c) 2023, Oracle and/or its affiliates.
+ */
+
+#include <linux/types.h>
+#include <linux/ipv6.h>
+
+#include <net/sock.h>
+#include <net/inet_sock.h>
+#include <net/netlink.h>
+#include <net/genetlink.h>
+
+#include "handshake.h"
+
+#define CREATE_TRACE_POINTS
+
+#include <trace/events/handshake.h>