[PATCH 02/16] nvme-tcp: sanitize TLS key handling

[Hannes Reinecke <hare@kernel.org>]

There is a difference between TLS configured (ie the user has
provisioned/requested a key) and TLS enabled (ie the connection
is encrypted with TLS). This becomes important for secure concatenation,
where the initial authentication is run unencrypted (ie with
TLS configured, but not enabled), and then the queue is reset to
run over TLS (ie TLS configured _and_ enabled).
So to differentiate between those two states store the provisioned
key in opts->tls_key (as we're using the same TLS key for all queues)
and only the key serial of the key negotiated by the TLS handshake
in queue->tls_pskid.

Signed-off-by: Hannes Reinecke <hare@kernel.org>
---
 drivers/nvme/host/core.c  |  1 -
 drivers/nvme/host/nvme.h  |  2 +-
 drivers/nvme/host/sysfs.c |  4 ++--
 drivers/nvme/host/tcp.c   | 47 ++++++++++++++++++++++++++++-----------
 4 files changed, 37 insertions(+), 17 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 8d8e7a3549c6..947f1e631ee5 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -4641,7 +4641,6 @@ static void nvme_free_ctrl(struct device *dev)
 
 	if (!subsys || ctrl->instance != subsys->instance)
 		ida_free(&nvme_instance_ida, ctrl->instance);
-	key_put(ctrl->tls_key);
 	nvme_free_cels(ctrl);
 	nvme_mpath_uninit(ctrl);
 	cleanup_srcu_struct(&ctrl->srcu);
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index c63f2b452369..cdb53323f4eb 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -370,7 +370,7 @@ struct nvme_ctrl {
 	struct nvme_dhchap_key *ctrl_key;
 	u16 transaction;
 #endif
-	struct key *tls_key;
+	key_serial_t tls_pskid;
 
 	/* Power saving configuration */
 	u64 ps_max_latency_us;
diff --git a/drivers/nvme/host/sysfs.c b/drivers/nvme/host/sysfs.c
index 3c55f7edd181..5b1dee8a66ef 100644
--- a/drivers/nvme/host/sysfs.c
+++ b/drivers/nvme/host/sysfs.c
@@ -671,9 +671,9 @@ static ssize_t tls_key_show(struct device *dev,
 {
 	struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
 
-	if (!ctrl->tls_key)
+	if (!ctrl->tls_pskid)
 		return 0;
-	return sysfs_emit(buf, "%08x", key_serial(ctrl->tls_key));
+	return sysfs_emit(buf, "%08x", ctrl->tls_pskid);
 }
 static DEVICE_ATTR_RO(tls_key);
 #endif
diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index a2a47d3ab99f..92ad5b8cc1b4 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -165,6 +165,7 @@ struct nvme_tcp_queue {
 
 	bool			hdr_digest;
 	bool			data_digest;
+	bool			tls_enabled;
 	struct ahash_request	*rcv_hash;
 	struct ahash_request	*snd_hash;
 	__le32			exp_ddgst;
@@ -213,7 +214,15 @@ static inline int nvme_tcp_queue_id(struct nvme_tcp_queue *queue)
 	return queue - queue->ctrl->queues;
 }
 
-static inline bool nvme_tcp_tls(struct nvme_ctrl *ctrl)
+static inline bool nvme_tcp_tls_enabled(struct nvme_tcp_queue *queue)
+{
+	if (!IS_ENABLED(CONFIG_NVME_TCP_TLS))
+		return 0;
+
+	return queue->tls_enabled;
+}
+
+static inline bool nvme_tcp_tls_configured(struct nvme_ctrl *ctrl)
 {
 	if (!IS_ENABLED(CONFIG_NVME_TCP_TLS))
 		return 0;
@@ -368,7 +377,7 @@ static inline bool nvme_tcp_queue_has_pending(struct nvme_tcp_queue *queue)
 
 static inline bool nvme_tcp_queue_more(struct nvme_tcp_queue *queue)
 {
-	return !nvme_tcp_tls(&queue->ctrl->ctrl) &&
+	return !nvme_tcp_tls_enabled(queue) &&
 		nvme_tcp_queue_has_pending(queue);
 }
 
@@ -1427,7 +1436,7 @@ static int nvme_tcp_init_connection(struct nvme_tcp_queue *queue)
 	memset(&msg, 0, sizeof(msg));
 	iov.iov_base = icresp;
 	iov.iov_len = sizeof(*icresp);
-	if (nvme_tcp_tls(&queue->ctrl->ctrl)) {
+	if (nvme_tcp_tls_enabled(queue)) {
 		msg.msg_control = cbuf;
 		msg.msg_controllen = sizeof(cbuf);
 	}
@@ -1439,7 +1448,7 @@ static int nvme_tcp_init_connection(struct nvme_tcp_queue *queue)
 		goto free_icresp;
 	}
 	ret = -ENOTCONN;
-	if (nvme_tcp_tls(&queue->ctrl->ctrl)) {
+	if (nvme_tcp_tls_enabled(queue)) {
 		ctype = tls_get_record_type(queue->sock->sk,
 					    (struct cmsghdr *)cbuf);
 		if (ctype != TLS_RECORD_TYPE_DATA) {
@@ -1587,7 +1596,10 @@ static void nvme_tcp_tls_done(void *data, int status, key_serial_t pskid)
 			 qid, pskid);
 		queue->tls_err = -ENOKEY;
 	} else {
-		ctrl->ctrl.tls_key = tls_key;
+		queue->tls_enabled = true;
+		if (qid == 0)
+			ctrl->ctrl.tls_pskid = key_serial(tls_key);
+		key_put(tls_key);
 		queue->tls_err = 0;
 	}
 
@@ -1768,7 +1780,7 @@ static int nvme_tcp_alloc_queue(struct nvme_ctrl *nctrl, int qid,
 	}
 
 	/* If PSKs are configured try to start TLS */
-	if (IS_ENABLED(CONFIG_NVME_TCP_TLS) && pskid) {
+	if (nvme_tcp_tls_configured(nctrl) && pskid) {
 		ret = nvme_tcp_start_tls(nctrl, queue, pskid);
 		if (ret)
 			goto err_init_connect;
@@ -1829,6 +1841,8 @@ static void nvme_tcp_stop_queue(struct nvme_ctrl *nctrl, int qid)
 	mutex_lock(&queue->queue_lock);
 	if (test_and_clear_bit(NVME_TCP_Q_LIVE, &queue->flags))
 		__nvme_tcp_stop_queue(queue);
+	/* Stopping the queue will disable TLS */
+	queue->tls_enabled = false;
 	mutex_unlock(&queue->queue_lock);
 }
 
@@ -1925,16 +1939,17 @@ static int nvme_tcp_alloc_admin_queue(struct nvme_ctrl *ctrl)
 	int ret;
 	key_serial_t pskid = 0;
 
-	if (nvme_tcp_tls(ctrl)) {
+	if (nvme_tcp_tls_configured(ctrl)) {
 		if (ctrl->opts->tls_key)
 			pskid = key_serial(ctrl->opts->tls_key);
-		else
+		else {
 			pskid = nvme_tls_psk_default(ctrl->opts->keyring,
 						      ctrl->opts->host->nqn,
 						      ctrl->opts->subsysnqn);
-		if (!pskid) {
-			dev_err(ctrl->device, "no valid PSK found\n");
-			return -ENOKEY;
+			if (!pskid) {
+				dev_err(ctrl->device, "no valid PSK found\n");
+				return -ENOKEY;
+			}
 		}
 	}
 
@@ -1957,13 +1972,14 @@ static int __nvme_tcp_alloc_io_queues(struct nvme_ctrl *ctrl)
 {
 	int i, ret;
 
-	if (nvme_tcp_tls(ctrl) && !ctrl->tls_key) {
+	if (nvme_tcp_tls_configured(ctrl) && !ctrl->tls_pskid) {
 		dev_err(ctrl->device, "no PSK negotiated\n");
 		return -ENOKEY;
 	}
+
 	for (i = 1; i < ctrl->queue_count; i++) {
 		ret = nvme_tcp_alloc_queue(ctrl, i,
-				key_serial(ctrl->tls_key));
+				ctrl->tls_pskid);
 		if (ret)
 			goto out_free_queues;
 	}
@@ -2144,6 +2160,11 @@ static void nvme_tcp_teardown_admin_queue(struct nvme_ctrl *ctrl,
 	if (remove)
 		nvme_unquiesce_admin_queue(ctrl);
 	nvme_tcp_destroy_admin_queue(ctrl, remove);
+	if (ctrl->tls_pskid) {
+		dev_dbg(ctrl->device, "Wipe negotiated TLS_PSK %08x\n",
+			ctrl->tls_pskid);
+		ctrl->tls_pskid = 0;
+	}
 }
 
 static void nvme_tcp_teardown_io_queues(struct nvme_ctrl *ctrl,
-- 
2.35.3