nvme-tcp: request secure channel concatenation

Add a fabrics option 'concat' to request secure channel concatenation as
specified the NVME Base Specification v2.1, section 8.3.4.3: Secure Channel
Concatenation.
When secure channel concatenation is enabled a 'generated PSK' is inserted
into the keyring such that it's available after reset.

Signed-off-by: Hannes Reinecke <hare@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Keith Busch <kbusch@kernel.org>

Author: Hannes Reinecke

drivers/nvme/host/Kconfig

@@ -109,7 +109,7 @@ config NVME_HOST_AUTH
 	bool "NVMe over Fabrics In-Band Authentication in host side"
 	depends on NVME_CORE
 	select NVME_AUTH
-	select NVME_KEYRING if NVME_TCP_TLS
+	select NVME_KEYRING
 	help
 	  This provides support for NVMe over Fabrics In-Band Authentication in
 	  host side.

drivers/nvme/host/auth.c

@@ -12,6 +12,7 @@
 #include "nvme.h"
 #include "fabrics.h"
 #include <linux/nvme-auth.h>
+#include <linux/nvme-keyring.h>
 
 #define CHAP_BUF_SIZE 4096
 static struct kmem_cache *nvme_chap_buf_cache;
@@ -131,7 +132,13 @@ static int nvme_auth_set_dhchap_negotiate_data(struct nvme_ctrl *ctrl,
 	data->auth_type = NVME_AUTH_COMMON_MESSAGES;
 	data->auth_id = NVME_AUTH_DHCHAP_MESSAGE_NEGOTIATE;
 	data->t_id = cpu_to_le16(chap->transaction);
-	data->sc_c = 0; /* No secure channel concatenation */
+	if (ctrl->opts->concat && chap->qid == 0) {
+		if (ctrl->opts->tls_key)
+			data->sc_c = NVME_AUTH_SECP_REPLACETLSPSK;
+		else
+			data->sc_c = NVME_AUTH_SECP_NEWTLSPSK;
+	} else
+		data->sc_c = NVME_AUTH_SECP_NOSC;
 	data->napd = 1;
 	data->auth_protocol[0].dhchap.authid = NVME_AUTH_DHCHAP_AUTH_ID;
 	data->auth_protocol[0].dhchap.halen = 3;
@@ -311,8 +318,9 @@ static int nvme_auth_set_dhchap_reply_data(struct nvme_ctrl *ctrl,
 	data->hl = chap->hash_len;
 	data->dhvlen = cpu_to_le16(chap->host_key_len);
 	memcpy(data->rval, chap->response, chap->hash_len);
-	if (ctrl->ctrl_key) {
+	if (ctrl->ctrl_key)
 		chap->bi_directional = true;
+	if (ctrl->ctrl_key || ctrl->opts->concat) {
 		get_random_bytes(chap->c2, chap->hash_len);
 		data->cvalid = 1;
 		memcpy(data->rval + chap->hash_len, chap->c2,
@@ -322,7 +330,10 @@ static int nvme_auth_set_dhchap_reply_data(struct nvme_ctrl *ctrl,
 	} else {
 		memset(chap->c2, 0, chap->hash_len);
 	}
-	chap->s2 = nvme_auth_get_seqnum();
+	if (ctrl->opts->concat)
+		chap->s2 = 0;
+	else
+		chap->s2 = nvme_auth_get_seqnum();
 	data->seqnum = cpu_to_le32(chap->s2);
 	if (chap->host_key_len) {
 		dev_dbg(ctrl->device, "%s: qid %d host public key %*ph\n",
@@ -677,6 +688,92 @@ static void nvme_auth_free_dhchap(struct nvme_dhchap_queue_context *chap)
 		crypto_free_kpp(chap->dh_tfm);
 }
 
+void nvme_auth_revoke_tls_key(struct nvme_ctrl *ctrl)
+{
+	dev_dbg(ctrl->device, "Wipe generated TLS PSK %08x\n",
+		key_serial(ctrl->opts->tls_key));
+	key_revoke(ctrl->opts->tls_key);
+	key_put(ctrl->opts->tls_key);
+	ctrl->opts->tls_key = NULL;
+}
+EXPORT_SYMBOL_GPL(nvme_auth_revoke_tls_key);
+
+static int nvme_auth_secure_concat(struct nvme_ctrl *ctrl,
+				   struct nvme_dhchap_queue_context *chap)
+{
+	u8 *psk, *digest, *tls_psk;
+	struct key *tls_key;
+	size_t psk_len;
+	int ret = 0;
+
+	if (!chap->sess_key) {
+		dev_warn(ctrl->device,
+			 "%s: qid %d no session key negotiated\n",
+			 __func__, chap->qid);
+		return -ENOKEY;
+	}
+
+	if (chap->qid) {
+		dev_warn(ctrl->device,
+			 "qid %d: secure concatenation not supported on I/O queues\n",
+			 chap->qid);
+		return -EINVAL;
+	}
+	ret = nvme_auth_generate_psk(chap->hash_id, chap->sess_key,
+				     chap->sess_key_len,
+				     chap->c1, chap->c2,
+				     chap->hash_len, &psk, &psk_len);
+	if (ret) {
+		dev_warn(ctrl->device,
+			 "%s: qid %d failed to generate PSK, error %d\n",
+			 __func__, chap->qid, ret);
+		return ret;
+	}
+	dev_dbg(ctrl->device,
+		  "%s: generated psk %*ph\n", __func__, (int)psk_len, psk);
+
+	ret = nvme_auth_generate_digest(chap->hash_id, psk, psk_len,
+					ctrl->opts->subsysnqn,
+					ctrl->opts->host->nqn, &digest);
+	if (ret) {
+		dev_warn(ctrl->device,
+			 "%s: qid %d failed to generate digest, error %d\n",
+			 __func__, chap->qid, ret);
+		goto out_free_psk;
+	};
+	dev_dbg(ctrl->device, "%s: generated digest %s\n",
+		 __func__, digest);
+	ret = nvme_auth_derive_tls_psk(chap->hash_id, psk, psk_len,
+				       digest, &tls_psk);
+	if (ret) {
+		dev_warn(ctrl->device,
+			 "%s: qid %d failed to derive TLS psk, error %d\n",
+			 __func__, chap->qid, ret);
+		goto out_free_digest;
+	};
+
+	tls_key = nvme_tls_psk_refresh(ctrl->opts->keyring,
+				       ctrl->opts->host->nqn,
+				       ctrl->opts->subsysnqn, chap->hash_id,
+				       tls_psk, psk_len, digest);
+	if (IS_ERR(tls_key)) {
+		ret = PTR_ERR(tls_key);
+		dev_warn(ctrl->device,
+			 "%s: qid %d failed to insert generated key, error %d\n",
+			 __func__, chap->qid, ret);
+		tls_key = NULL;
+	}
+	kfree_sensitive(tls_psk);
+	if (ctrl->opts->tls_key)
+		nvme_auth_revoke_tls_key(ctrl);
+	ctrl->opts->tls_key = tls_key;
+out_free_digest:
+	kfree_sensitive(digest);
+out_free_psk:
+	kfree_sensitive(psk);
+	return ret;
+}
+
 static void nvme_queue_auth_work(struct work_struct *work)
 {
 	struct nvme_dhchap_queue_context *chap =
@@ -833,6 +930,13 @@ static void nvme_queue_auth_work(struct work_struct *work)
 	}
 	if (!ret) {
 		chap->error = 0;
+		if (ctrl->opts->concat &&
+		    (ret = nvme_auth_secure_concat(ctrl, chap))) {
+			dev_warn(ctrl->device,
+				 "%s: qid %d failed to enable secure concatenation\n",
+				 __func__, chap->qid);
+			chap->error = ret;
+		}
 		return;
 	}
 
@@ -912,6 +1016,11 @@ static void nvme_ctrl_auth_work(struct work_struct *work)
 			 "qid 0: authentication failed\n");
 		return;
 	}
+	/*
+	 * Only run authentication on the admin queue for secure concatenation.
+	 */
+	if (ctrl->opts->concat)
+		return;
 
 	for (q = 1; q < ctrl->queue_count; q++) {
 		ret = nvme_auth_negotiate(ctrl, q);

drivers/nvme/host/fabrics.c

@@ -472,8 +472,9 @@ int nvmf_connect_admin_queue(struct nvme_ctrl *ctrl)
 	result = le32_to_cpu(res.u32);
 	ctrl->cntlid = result & 0xFFFF;
 	if (result & (NVME_CONNECT_AUTHREQ_ATR | NVME_CONNECT_AUTHREQ_ASCR)) {
-		/* Secure concatenation is not implemented */
-		if (result & NVME_CONNECT_AUTHREQ_ASCR) {
+		/* Check for secure concatenation */
+		if ((result & NVME_CONNECT_AUTHREQ_ASCR) &&
+		    !ctrl->opts->concat) {
 			dev_warn(ctrl->device,
 				 "qid 0: secure concatenation is not supported\n");
 			ret = -EOPNOTSUPP;
@@ -550,7 +551,7 @@ int nvmf_connect_io_queue(struct nvme_ctrl *ctrl, u16 qid)
 		/* Secure concatenation is not implemented */
 		if (result & NVME_CONNECT_AUTHREQ_ASCR) {
 			dev_warn(ctrl->device,
-				 "qid 0: secure concatenation is not supported\n");
+				 "qid %d: secure concatenation is not supported\n", qid);
 			ret = -EOPNOTSUPP;
 			goto out_free_data;
 		}
@@ -706,6 +707,7 @@ static const match_table_t opt_tokens = {
 #endif
 #ifdef CONFIG_NVME_TCP_TLS
 	{ NVMF_OPT_TLS,			"tls"			},
+	{ NVMF_OPT_CONCAT,		"concat"		},
 #endif
 	{ NVMF_OPT_ERR,			NULL			}
 };
@@ -735,6 +737,7 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
 	opts->tls = false;
 	opts->tls_key = NULL;
 	opts->keyring = NULL;
+	opts->concat = false;
 
 	options = o = kstrdup(buf, GFP_KERNEL);
 	if (!options)
@@ -1053,6 +1056,14 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
 			}
 			opts->tls = true;
 			break;
+		case NVMF_OPT_CONCAT:
+			if (!IS_ENABLED(CONFIG_NVME_TCP_TLS)) {
+				pr_err("TLS is not supported\n");
+				ret = -EINVAL;
+				goto out;
+			}
+			opts->concat = true;
+			break;
 		default:
 			pr_warn("unknown parameter or missing value '%s' in ctrl creation request\n",
 				p);
@@ -1079,6 +1090,23 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
 			pr_warn("failfast tmo (%d) larger than controller loss tmo (%d)\n",
 				opts->fast_io_fail_tmo, ctrl_loss_tmo);
 	}
+	if (opts->concat) {
+		if (opts->tls) {
+			pr_err("Secure concatenation over TLS is not supported\n");
+			ret = -EINVAL;
+			goto out;
+		}
+		if (opts->tls_key) {
+			pr_err("Cannot specify a TLS key for secure concatenation\n");
+			ret = -EINVAL;
+			goto out;
+		}
+		if (!opts->dhchap_secret) {
+			pr_err("Need to enable DH-CHAP for secure concatenation\n");
+			ret = -EINVAL;
+			goto out;
+		}
+	}
 
 	opts->host = nvmf_host_add(hostnqn, &hostid);
 	if (IS_ERR(opts->host)) {

drivers/nvme/host/fabrics.h

@@ -66,6 +66,7 @@ enum {
 	NVMF_OPT_TLS		= 1 << 25,
 	NVMF_OPT_KEYRING	= 1 << 26,
 	NVMF_OPT_TLS_KEY	= 1 << 27,
+	NVMF_OPT_CONCAT		= 1 << 28,
 };
 
 /**
@@ -101,6 +102,7 @@ enum {
  * @keyring:    Keyring to use for key lookups
  * @tls_key:    TLS key for encrypted connections (TCP)
  * @tls:        Start TLS encrypted connections (TCP)
+ * @concat:     Enabled Secure channel concatenation (TCP)
  * @disable_sqflow: disable controller sq flow control
  * @hdr_digest: generate/verify header digest (TCP)
  * @data_digest: generate/verify data digest (TCP)
@@ -130,6 +132,7 @@ struct nvmf_ctrl_options {
 	struct key		*keyring;
 	struct key		*tls_key;
 	bool			tls;
+	bool			concat;
 	bool			disable_sqflow;
 	bool			hdr_digest;
 	bool			data_digest;

drivers/nvme/host/nvme.h

@@ -1147,6 +1147,7 @@ void nvme_auth_stop(struct nvme_ctrl *ctrl);
 int nvme_auth_negotiate(struct nvme_ctrl *ctrl, int qid);
 int nvme_auth_wait(struct nvme_ctrl *ctrl, int qid);
 void nvme_auth_free(struct nvme_ctrl *ctrl);
+void nvme_auth_revoke_tls_key(struct nvme_ctrl *ctrl);
 #else
 static inline int nvme_auth_init_ctrl(struct nvme_ctrl *ctrl)
 {
@@ -1169,6 +1170,7 @@ static inline int nvme_auth_wait(struct nvme_ctrl *ctrl, int qid)
 	return -EPROTONOSUPPORT;
 }
 static inline void nvme_auth_free(struct nvme_ctrl *ctrl) {};
+static inline void nvme_auth_revoke_tls_key(struct nvme_ctrl *ctrl) {};
 #endif
 
 u32 nvme_command_effects(struct nvme_ctrl *ctrl, struct nvme_ns *ns,

drivers/nvme/host/sysfs.c

@@ -780,10 +780,10 @@ static umode_t nvme_tls_attrs_are_visible(struct kobject *kobj,
 		return 0;
 
 	if (a == &dev_attr_tls_key.attr &&
-	    !ctrl->opts->tls)
+	    !ctrl->opts->tls && !ctrl->opts->concat)
 		return 0;
 	if (a == &dev_attr_tls_configured_key.attr &&
-	    !ctrl->opts->tls_key)
+	    (!ctrl->opts->tls_key || ctrl->opts->concat))
 		return 0;
 	if (a == &dev_attr_tls_keyring.attr &&
 	    !ctrl->opts->keyring)