[PATCH 16/17] nvmet-tcp: enable TLS handshake upcall

Hannes Reinecke
2023-08-11T12:18:46Z

Add functions to start the TLS handshake upcall when
the TCP TSAS sectype is set to 'tls1.3' and add a config
option NVME_TARGET_TCP_TLS.
And move the 'state' lock to an irq-safe lock as the 'done'
callback from the TLS handshake will be running in interrupt
context.

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 | 139 ++++++++++++++++++++++++++++++++-
4 files changed, 173 insertions(+), 3 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 84b726dfc1c4..ca4aa8870876 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
@@ -122,6 +136,7 @@ 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,
};
@@ -156,6 +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;
@@ -1290,7 +1309,8 @@ static int nvmet_tcp_try_recv(struct nvmet_tcp_queue *queue,
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) {
+ if (queue->state != NVMET_TCP_Q_TLS_HANDSHAKE &&
+ queue->state != NVMET_TCP_Q_DISCONNECTING) {
queue->state = NVMET_TCP_Q_DISCONNECTING;
queue_work(nvmet_wq, &queue->release_work);
}
@@ -1547,7 +1567,11 @@ static void nvmet_tcp_data_ready(struct sock *sk)
read_lock_bh(&sk->sk_callback_lock);
queue = sk->sk_user_data;
if (likely(nvmet_tcp_get_queue(queue))) {
- queue_work_on(queue_cpu(queue), nvmet_tcp_wq, &queue->io_work);
+ 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);
nvmet_tcp_put_queue(queue);
}
read_unlock_bh(&sk->sk_callback_lock);
@@ -1660,6 +1684,91 @@ 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) {
+ pr_warn("queue %d: TLS handshake already completed\n",
+ queue->idx);
+ spin_unlock_bh(&queue->state_lock);
+ /*
+ * Do not decrease the refcount here, as we only
+ * take a single reference in nvmet_tcp_tls_handshake()
+ */
+ return;
+ }
+ if (!status)
+ queue->tls_pskid = peerid;
+ queue->state = NVMET_TCP_Q_CONNECTING;
+ spin_unlock_bh(&queue->state_lock);
+
+ cancel_delayed_work_sync(&queue->tls_handshake_work);
+ if (status) {
+ pr_debug("queue %d: TLS handshake error %d, resetting\n",
+ queue->idx, status);
+ nvmet_tcp_schedule_release_queue(queue);
+ nvmet_tcp_put_queue(queue);
+ return;
+ }
+
+ pr_debug("queue %d: resetting queue callbacks after TLS handshake\n",
+ queue->idx);
+ nvmet_tcp_set_queue_sock(queue);
+ nvmet_tcp_put_queue(queue);
+}
+
+static void nvmet_tcp_tls_handshake_timeout_work(struct work_struct *w)
+{
+ struct nvmet_tcp_queue *queue = container_of(to_delayed_work(w),
+ struct nvmet_tcp_queue, tls_handshake_work);
+
+ pr_debug("queue %d: TLS handshake timeout\n", queue->idx);
+ nvmet_tcp_tls_handshake_done((void *)queue, -ETIMEDOUT, 0);
+}
+
+static int nvmet_tcp_tls_handshake(struct nvmet_tcp_queue *queue)
+{
+ int ret = -EOPNOTSUPP;
+ struct tls_handshake_args args;
+
+ if (!nvmet_tcp_get_queue(queue)) {
+ pr_warn("queue %d: cannot start TLS, queue freed\n", queue->idx);
+ return -EINVAL;
+ }
+ if (queue->state != NVMET_TCP_Q_TLS_HANDSHAKE) {
+ pr_warn("queue %d: cannot start TLS in state %d\n",
+ queue->idx, queue->state);
+ nvmet_tcp_put_queue(queue);
+ return -EINVAL;
+ }
+
+ 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) {
+ pr_err("queue %d: failed to start TLS, err=%d\n",
+ queue->idx, ret);
+ nvmet_tcp_put_queue(queue);
+ } 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)
{
@@ -1680,7 +1789,11 @@ static void nvmet_tcp_alloc_queue(struct nvmet_tcp_port *port,
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);
@@ -1711,10 +1824,30 @@ 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)
return;

+out_destroy_sq:
queue->state = NVMET_TCP_Q_DISCONNECTING;
mutex_lock(&nvmet_tcp_queue_mutex);
list_del_init(&queue->queue_list);
--
2.35.3