[PATCH 08/17] nvme-tcp: sanitize TLS key handling

[Hannes Reinecke <hare@kernel.org>]

From: Hannes Reinecke <hare@suse.de>

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@suse.de>
---
 drivers/nvme/host/core.c  |  1 -
 drivers/nvme/host/sysfs.c |  2 +-
 drivers/nvme/host/tcp.c   | 54 +++++++++++++++++++++++++++++----------
 3 files changed, 42 insertions(+), 15 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 2baf5786a92f..9b601655f423 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -4567,7 +4567,6 @@ 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);
 	nvme_auth_stop(ctrl);
diff --git a/drivers/nvme/host/sysfs.c b/drivers/nvme/host/sysfs.c
index ec581608f16c..1f9e57fbfee3 100644
--- a/drivers/nvme/host/sysfs.c
+++ b/drivers/nvme/host/sysfs.c
@@ -671,7 +671,7 @@ static ssize_t tls_key_show(struct device *dev,
 			    struct device_attribute *attr, char *buf)
 {
 	struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
-	struct key *key = ctrl->tls_key;
+	struct key *key = ctrl->opts->tls_key;
 
 	if (!key)
 		return 0;
diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 4a58886e1354..7018dc0dd026 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -163,6 +163,7 @@ struct nvme_tcp_queue {
 	__le32			recv_ddgst;
 	struct completion       tls_complete;
 	int                     tls_err;
+	key_serial_t		tls_pskid;
 	struct page_frag_cache	pf_cache;
 
 	void (*state_change)(struct sock *);
@@ -205,7 +206,15 @@ 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_pskid != 0);
+}
+
+static inline bool nvme_tcp_tls_configured(struct nvme_ctrl *ctrl)
 {
 	if (!IS_ENABLED(CONFIG_NVME_TCP_TLS))
 		return 0;
@@ -1418,7 +1427,7 @@ 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);
 	}
@@ -1430,7 +1439,7 @@ 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) {
@@ -1581,7 +1590,11 @@ static void nvme_tcp_tls_done(void *data, int status, key_serial_t pskid)
 		key_put(tls_key);
 		queue->tls_err = -EKEYREVOKED;
 	} else {
-		ctrl->ctrl.tls_key = tls_key;
+		queue->tls_pskid = key_serial(tls_key);
+		if (qid == 0)
+			ctrl->ctrl.tls_key = tls_key;
+		else
+			key_put(tls_key);
 		queue->tls_err = 0;
 	}
 
@@ -1762,7 +1775,7 @@ 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;
@@ -1823,6 +1836,12 @@ 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, so clear the PSK ID */
+	if (queue->tls_pskid) {
+		dev_dbg(nctrl->device, "queue %d clear TLS PSK %08x\n",
+			qid, queue->tls_pskid);
+		queue->tls_pskid = 0;
+	}
 	mutex_unlock(&queue->queue_lock);
 }
 
@@ -1919,16 +1938,17 @@ 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;
+			}
 		}
 	}
 
@@ -1949,15 +1969,17 @@ static int nvme_tcp_alloc_admin_queue(struct nvme_ctrl *ctrl)
 
 static int __nvme_tcp_alloc_io_queues(struct nvme_ctrl *ctrl)
 {
+	struct nvme_tcp_ctrl *tcp_ctrl = to_tcp_ctrl(ctrl);
+	key_serial_t pskid = ctrl->tls_key ? key_serial(ctrl->tls_key) : 0;
 	int i, ret;
 
-	if (nvme_tcp_tls(ctrl) && !ctrl->tls_key) {
+	if (nvme_tcp_tls_configured(ctrl) && !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));
+		ret = nvme_tcp_alloc_queue(ctrl, i, pskid);
 		if (ret)
 			goto out_free_queues;
 	}
@@ -2138,6 +2160,12 @@ 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_key) {
+		dev_dbg(ctrl->device, "Wipe negotiated TLS_PSK %08x\n",
+			key_serial(ctrl->tls_key));
+		key_put(ctrl->tls_key);
+		ctrl->tls_key = NULL;
+	}
 }
 
 static void nvme_tcp_teardown_io_queues(struct nvme_ctrl *ctrl,
-- 
2.35.3