Re: [PATCH 15/17] nvmet-tcp: enable TLS handshake upcall

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
  drivers/nvme/target/Kconfig    |  15 ++++
  drivers/nvme/target/configfs.c |  21 +++++
  drivers/nvme/target/nvmet.h    |   1 +
  drivers/nvme/target/tcp.c      | 146 ++++++++++++++++++++++++++++++++-
  4 files changed, 179 insertions(+), 4 deletions(-)

diff --git a/drivers/nvme/target/Kconfig b/drivers/nvme/target/Kconfig
index 79fc64035ee3..8a6c9cae804c 100644
--- a/drivers/nvme/target/Kconfig
+++ b/drivers/nvme/target/Kconfig

@@ -84,6 +84,21 @@ config NVME_TARGET_TCP
  
  	  If unsure, say N.
  
+config NVME_TARGET_TCP_TLS
+	bool "NVMe over Fabrics TCP target TLS encryption support"
+	depends on NVME_TARGET_TCP
+	select NVME_COMMON
+	select NVME_KEYRING
+	select NET_HANDSHAKE
+	select KEYS
+	help
+	  Enables TLS encryption for the NVMe TCP target using the netlink handshake API.
+
+	  The TLS handshake daemon is availble at
+	  https://github.com/oracle/ktls-utils.
+
+	  If unsure, say N.
+
  config NVME_TARGET_AUTH
  	bool "NVMe over Fabrics In-band Authentication support"
  	depends on NVME_TARGET

diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c
index efbfed310370..ad1fb32c7387 100644
--- a/drivers/nvme/target/configfs.c
+++ b/drivers/nvme/target/configfs.c

@@ -15,6 +15,7 @@
  #ifdef CONFIG_NVME_TARGET_AUTH
  #include <linux/nvme-auth.h>
  #endif
+#include <linux/nvme-keyring.h>
  #include <crypto/hash.h>
  #include <crypto/kpp.h>
  

@@ -397,6 +398,17 @@ static ssize_t nvmet_addr_tsas_store(struct config_item *item,
  	return -EINVAL;
  
  found:
+	if (sectype == NVMF_TCP_SECTYPE_TLS13) {
+		if (!IS_ENABLED(CONFIG_NVME_TARGET_TCP_TLS)) {
+			pr_err("TLS is not supported\n");
+			return -EINVAL;
+		}
+		if (!port->keyring) {
+			pr_err("TLS keyring not configured\n");
+			return -EINVAL;
+		}
+	}
+
  	nvmet_port_init_tsas_tcp(port, sectype);
  	/*
  	 * The TLS implementation currently does not support

@@ -1815,6 +1827,7 @@ static void nvmet_port_release(struct config_item *item)
  	flush_workqueue(nvmet_wq);
  	list_del(&port->global_entry);
  
+	key_put(port->keyring);
  	kfree(port->ana_state);
  	kfree(port);
  }

@@ -1864,6 +1877,14 @@ static struct config_group *nvmet_ports_make(struct config_group *group,
  		return ERR_PTR(-ENOMEM);
  	}
  
+	if (nvme_keyring_id()) {
+		port->keyring = key_lookup(nvme_keyring_id());
+		if (IS_ERR(port->keyring)) {
+			pr_warn("NVMe keyring not available, disabling TLS\n");
+			port->keyring = NULL;

+		}
+	}
+
  	for (i = 1; i <= NVMET_MAX_ANAGRPS; i++) {
  		if (i == NVMET_DEFAULT_ANA_GRPID)
  			port->ana_state[1] = NVME_ANA_OPTIMIZED;

diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index 8cfd60f3b564..7f9ae53c1df5 100644
--- a/drivers/nvme/target/nvmet.h
+++ b/drivers/nvme/target/nvmet.h

@@ -158,6 +158,7 @@ struct nvmet_port {
  	struct config_group		ana_groups_group;
  	struct nvmet_ana_group		ana_default_group;
  	enum nvme_ana_state		*ana_state;
+	struct key			*keyring;
  	void				*priv;
  	bool				enabled;
  	int				inline_data_size;

diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c
index f19ea9d923fd..77fa339008e1 100644
--- a/drivers/nvme/target/tcp.c
+++ b/drivers/nvme/target/tcp.c

@@ -8,9 +8,13 @@
  #include <linux/init.h>
  #include <linux/slab.h>
  #include <linux/err.h>
+#include <linux/key.h>
  #include <linux/nvme-tcp.h>
+#include <linux/nvme-keyring.h>
  #include <net/sock.h>
  #include <net/tcp.h>
+#include <net/tls.h>
+#include <net/handshake.h>
  #include <linux/inet.h>
  #include <linux/llist.h>
  #include <crypto/hash.h>

@@ -66,6 +70,16 @@ device_param_cb(idle_poll_period_usecs, &set_param_ops,
  MODULE_PARM_DESC(idle_poll_period_usecs,
  		"nvmet tcp io_work poll till idle time period in usecs: Default 0");
  
+#ifdef CONFIG_NVME_TARGET_TCP_TLS
+/*
+ * TLS handshake timeout
+ */
+static int tls_handshake_timeout = 10;
+module_param(tls_handshake_timeout, int, 0644);
+MODULE_PARM_DESC(tls_handshake_timeout,
+		 "nvme TLS handshake timeout in seconds (default 10)");
+#endif
+
  #define NVMET_TCP_RECV_BUDGET		8
  #define NVMET_TCP_SEND_BUDGET		8
  #define NVMET_TCP_IO_WORK_BUDGET	64

@@ -122,11 +136,13 @@ struct nvmet_tcp_cmd {
  
  enum nvmet_tcp_queue_state {
  	NVMET_TCP_Q_CONNECTING,
+	NVMET_TCP_Q_TLS_HANDSHAKE,
  	NVMET_TCP_Q_LIVE,
  	NVMET_TCP_Q_DISCONNECTING,
  };
  
  struct nvmet_tcp_queue {
+	struct kref		kref;

  	struct socket		*sock;
  	struct nvmet_tcp_port	*port;
  	struct work_struct	io_work;

@@ -155,6 +171,10 @@ struct nvmet_tcp_queue {
  	struct ahash_request	*snd_hash;
  	struct ahash_request	*rcv_hash;
  
+	/* TLS state */
+	key_serial_t		tls_pskid;
+	struct delayed_work	tls_handshake_work;
+
  	unsigned long           poll_end;
  
  	spinlock_t		state_lock;

@@ -1283,12 +1303,21 @@ static int nvmet_tcp_try_recv(struct nvmet_tcp_queue *queue,
  	return ret;
  }
  
+static void nvmet_tcp_release_queue(struct kref *kref)
+{
+	struct nvmet_tcp_queue *queue =
+		container_of(kref, struct nvmet_tcp_queue, kref);
+
+	WARN_ON(queue->state != NVMET_TCP_Q_DISCONNECTING);
+	queue_work(nvmet_wq, &queue->release_work);
+}
+
  static void nvmet_tcp_schedule_release_queue(struct nvmet_tcp_queue *queue)
  {
  	spin_lock_bh(&queue->state_lock);
  	if (queue->state != NVMET_TCP_Q_DISCONNECTING) {
  		queue->state = NVMET_TCP_Q_DISCONNECTING;
-		queue_work(nvmet_wq, &queue->release_work);
+		kref_put(&queue->kref, nvmet_tcp_release_queue);
  	}
  	spin_unlock_bh(&queue->state_lock);
  }

@@ -1485,6 +1514,8 @@ static void nvmet_tcp_release_queue_work(struct work_struct *w)
  	mutex_unlock(&nvmet_tcp_queue_mutex);
  
  	nvmet_tcp_restore_socket_callbacks(queue);
+	tls_handshake_cancel(queue->sock->sk);
+	cancel_delayed_work_sync(&queue->tls_handshake_work);

  	cancel_work_sync(&queue->io_work);
  	/* stop accepting incoming data */
  	queue->rcv_state = NVMET_TCP_RECV_ERR;

@@ -1512,8 +1543,13 @@ static void nvmet_tcp_data_ready(struct sock *sk)
  
  	read_lock_bh(&sk->sk_callback_lock);
  	queue = sk->sk_user_data;
-	if (likely(queue))
-		queue_work_on(queue_cpu(queue), nvmet_tcp_wq, &queue->io_work);
+	if (likely(queue)) {
+		if (queue->data_ready)
+			queue->data_ready(sk);
+		if (queue->state != NVMET_TCP_Q_TLS_HANDSHAKE)
+			queue_work_on(queue_cpu(queue), nvmet_tcp_wq,
+				      &queue->io_work);
+	}
  	read_unlock_bh(&sk->sk_callback_lock);
  }
  

@@ -1621,6 +1657,83 @@ static int nvmet_tcp_set_queue_sock(struct nvmet_tcp_queue *queue)
  	return ret;
  }
  
+#ifdef CONFIG_NVME_TARGET_TCP_TLS
+static void nvmet_tcp_tls_handshake_done(void *data, int status,
+					 key_serial_t peerid)
+{
+	struct nvmet_tcp_queue *queue = data;
+
+	pr_debug("queue %d: TLS handshake done, key %x, status %d\n",
+		 queue->idx, peerid, status);
+	spin_lock_bh(&queue->state_lock);
+	if (queue->state != NVMET_TCP_Q_TLS_HANDSHAKE) {

+	kref_put(&queue->kref, nvmet_tcp_release_queue);
+}
+
+static int nvmet_tcp_tls_handshake(struct nvmet_tcp_queue *queue)
+{
+	int ret = -EOPNOTSUPP;
+	struct tls_handshake_args args;
+
+	if (queue->state != NVMET_TCP_Q_TLS_HANDSHAKE) {
+		pr_warn("cannot start TLS in state %d\n", queue->state);
+		return -EINVAL;
+	}
+
+	kref_get(&queue->kref);
+	pr_debug("queue %d: TLS ServerHello\n", queue->idx);
+	memset(&args, 0, sizeof(args));
+	args.ta_sock = queue->sock;
+	args.ta_done = nvmet_tcp_tls_handshake_done;
+	args.ta_data = 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 (ret) {
+		kref_put(&queue->kref, nvmet_tcp_release_queue);
+		pr_err("failed to start TLS, err=%d\n", ret);
+	} else {
+		queue_delayed_work(nvmet_wq, &queue->tls_handshake_work,
+				   tls_handshake_timeout * HZ);
+	}
+	return ret;
+}
+#endif
+
  static void nvmet_tcp_alloc_queue(struct nvmet_tcp_port *port,
  		struct socket *newsock)
  {

@@ -1636,11 +1749,16 @@ static void nvmet_tcp_alloc_queue(struct nvmet_tcp_port *port,
  
  	INIT_WORK(&queue->release_work, nvmet_tcp_release_queue_work);
  	INIT_WORK(&queue->io_work, nvmet_tcp_io_work);
+	kref_init(&queue->kref);
  	queue->sock = newsock;
  	queue->port = port;
  	queue->nr_cmds = 0;
  	spin_lock_init(&queue->state_lock);
-	queue->state = NVMET_TCP_Q_CONNECTING;
+	if (queue->port->nport->disc_addr.tsas.tcp.sectype ==
+	    NVMF_TCP_SECTYPE_TLS13)
+		queue->state = NVMET_TCP_Q_TLS_HANDSHAKE;
+	else
+		queue->state = NVMET_TCP_Q_CONNECTING;
  	INIT_LIST_HEAD(&queue->free_list);
  	init_llist_head(&queue->resp_list);
  	INIT_LIST_HEAD(&queue->resp_send_list);

@@ -1671,12 +1789,32 @@ static void nvmet_tcp_alloc_queue(struct nvmet_tcp_port *port,
  	list_add_tail(&queue->queue_list, &nvmet_tcp_queue_list);
  	mutex_unlock(&nvmet_tcp_queue_mutex);
  
+#ifdef CONFIG_NVME_TARGET_TCP_TLS
+	INIT_DELAYED_WORK(&queue->tls_handshake_work,
+			  nvmet_tcp_tls_handshake_timeout_work);
+	if (queue->state == NVMET_TCP_Q_TLS_HANDSHAKE) {
+		struct sock *sk = queue->sock->sk;
+
+		/* Restore the default callbacks before starting upcall */
+		read_lock_bh(&sk->sk_callback_lock);
+		sk->sk_user_data = NULL;
+		sk->sk_data_ready = port->data_ready;
+		read_unlock_bh(&sk->sk_callback_lock);
+		if (!nvmet_tcp_tls_handshake(queue))
+			return;
+
+		/* TLS handshake failed, terminate the connection */
+		goto out_destroy_sq;
+	}
+#endif
+
  	ret = nvmet_tcp_set_queue_sock(queue);
  	if (ret)
  		goto out_destroy_sq;
  
  	return;
  out_destroy_sq:
+	queue->state = NVMET_TCP_Q_DISCONNECTING;