[PATCH 09/10] nvmet-tcp: support secure channel concatenation

Hannes Reinecke
2025-02-24T13:14:33Z

Evaluate the SC_C flag during DH-CHAP-HMAC negotiation to check if secure
concatenation as specified in the NVMe Base Specification v2.1, section
8.3.4.3: "Secure Channel Concatenationand" is requested. If requested the
generated PSK is inserted into the keyring once negotiation has finished
allowing for an encrypted connection once the admin queue is restarted.

Signed-off-by: Hannes Reinecke <hare@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
---
drivers/nvme/target/auth.c | 70 ++++++++++++++++++++++++++
drivers/nvme/target/core.c | 5 +-
drivers/nvme/target/fabrics-cmd-auth.c | 58 +++++++++++++++++++--
drivers/nvme/target/fabrics-cmd.c | 16 +++++-
drivers/nvme/target/nvmet.h | 32 ++++++++++--
drivers/nvme/target/tcp.c | 31 +++++++++++-
6 files changed, 199 insertions(+), 13 deletions(-)

diff --git a/drivers/nvme/target/auth.c b/drivers/nvme/target/auth.c
index d0392ccda2a1..0b0645ac5df4 100644
--- a/drivers/nvme/target/auth.c
+++ b/drivers/nvme/target/auth.c
@@ -15,6 +15,7 @@
#include <linux/ctype.h>
#include <linux/random.h>
#include <linux/nvme-auth.h>
+#include <linux/nvme-keyring.h>
#include <linux/unaligned.h>

#include "nvmet.h"
@@ -165,6 +166,11 @@ u8 nvmet_setup_auth(struct nvmet_ctrl *ctrl, struct nvmet_sq *sq)
goto out_unlock;
}

+ if (nvmet_queue_tls_keyid(sq)) {
+ pr_debug("host %s tls enabled\n", ctrl->hostnqn);
+ goto out_unlock;
+ }
+
ret = nvmet_setup_dhgroup(ctrl, host->dhchap_dhgroup_id);
if (ret < 0) {
pr_warn("Failed to setup DH group");
@@ -233,6 +239,9 @@ u8 nvmet_setup_auth(struct nvmet_ctrl *ctrl, struct nvmet_sq *sq)
void nvmet_auth_sq_free(struct nvmet_sq *sq)
{
cancel_delayed_work(&sq->auth_expired_work);
+#ifdef CONFIG_NVME_TARGET_TCP_TLS
+ sq->tls_key = 0;
+#endif
kfree(sq->dhchap_c1);
sq->dhchap_c1 = NULL;
kfree(sq->dhchap_c2);
@@ -261,6 +270,12 @@ void nvmet_destroy_auth(struct nvmet_ctrl *ctrl)
nvme_auth_free_key(ctrl->ctrl_key);
ctrl->ctrl_key = NULL;
}
+#ifdef CONFIG_NVME_TARGET_TCP_TLS
+ if (ctrl->tls_key) {
+ key_put(ctrl->tls_key);
+ ctrl->tls_key = NULL;
+ }
+#endif
}

bool nvmet_check_auth_status(struct nvmet_req *req)
@@ -542,3 +557,58 @@ int nvmet_auth_ctrl_sesskey(struct nvmet_req *req,

return ret;
}
+
+void nvmet_auth_insert_psk(struct nvmet_sq *sq)
+{
+ int hash_len = nvme_auth_hmac_hash_len(sq->ctrl->shash_id);
+ u8 *psk, *digest, *tls_psk;
+ size_t psk_len;
+ int ret;
+#ifdef CONFIG_NVME_TARGET_TCP_TLS
+ struct key *tls_key = NULL;
+#endif
+
+ ret = nvme_auth_generate_psk(sq->ctrl->shash_id,
+ sq->dhchap_skey,
+ sq->dhchap_skey_len,
+ sq->dhchap_c1, sq->dhchap_c2,
+ hash_len, &psk, &psk_len);
+ if (ret) {
+ pr_warn("%s: ctrl %d qid %d failed to generate PSK, error %d\n",
+ __func__, sq->ctrl->cntlid, sq->qid, ret);
+ return;
+ }
+ ret = nvme_auth_generate_digest(sq->ctrl->shash_id, psk, psk_len,
+ sq->ctrl->subsysnqn,
+ sq->ctrl->hostnqn, &digest);
+ if (ret) {
+ pr_warn("%s: ctrl %d qid %d failed to generate digest, error %d\n",
+ __func__, sq->ctrl->cntlid, sq->qid, ret);
+ goto out_free_psk;
+ }
+ ret = nvme_auth_derive_tls_psk(sq->ctrl->shash_id, psk, psk_len,
+ digest, &tls_psk);
+ if (ret) {
+ pr_warn("%s: ctrl %d qid %d failed to derive TLS PSK, error %d\n",
+ __func__, sq->ctrl->cntlid, sq->qid, ret);
+ goto out_free_digest;
+ }
+#ifdef CONFIG_NVME_TARGET_TCP_TLS
+ tls_key = nvme_tls_psk_refresh(NULL, sq->ctrl->hostnqn, sq->ctrl->subsysnqn,
+ sq->ctrl->shash_id, tls_psk, psk_len, digest);
+ if (IS_ERR(tls_key)) {
+ pr_warn("%s: ctrl %d qid %d failed to refresh key, error %ld\n",
+ __func__, sq->ctrl->cntlid, sq->qid, PTR_ERR(tls_key));
+ tls_key = NULL;
+ kfree_sensitive(tls_psk);
+ }
+ if (sq->ctrl->tls_key)
+ key_put(sq->ctrl->tls_key);
+ sq->ctrl->tls_key = tls_key;
+#endif
+
+out_free_digest:
+ kfree_sensitive(digest);
+out_free_psk:
+ kfree_sensitive(psk);
+}
diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index c2563c39581b..bc17ec4a783a 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -1646,11 +1646,12 @@ struct nvmet_ctrl *nvmet_alloc_ctrl(struct nvmet_alloc_ctrl_args *args)

args->status = NVME_SC_SUCCESS;

- pr_info("Created %s controller %d for subsystem %s for NQN %s%s%s.\n",
+ pr_info("Created %s controller %d for subsystem %s for NQN %s%s%s%s.\n",
nvmet_is_disc_subsys(ctrl->subsys) ? "discovery" : "nvm",
ctrl->cntlid, ctrl->subsys->subsysnqn, ctrl->hostnqn,
ctrl->pi_support ? " T10-PI is enabled" : "",
- nvmet_has_auth(ctrl) ? " with DH-HMAC-CHAP" : "");
+ nvmet_has_auth(ctrl, args->sq) ? " with DH-HMAC-CHAP" : "",
+ nvmet_queue_tls_keyid(args->sq) ? ", TLS" : "");

return ctrl;

diff --git a/drivers/nvme/target/fabrics-cmd-auth.c b/drivers/nvme/target/fabrics-cmd-auth.c
index 43b684af816c..bf01ec414c55 100644
--- a/drivers/nvme/target/fabrics-cmd-auth.c
+++ b/drivers/nvme/target/fabrics-cmd-auth.c
@@ -43,8 +43,26 @@ static u8 nvmet_auth_negotiate(struct nvmet_req *req, void *d)
data->auth_protocol[0].dhchap.halen,
data->auth_protocol[0].dhchap.dhlen);
req->sq->dhchap_tid = le16_to_cpu(data->t_id);
- if (data->sc_c)
- return NVME_AUTH_DHCHAP_FAILURE_CONCAT_MISMATCH;
+ if (data->sc_c != NVME_AUTH_SECP_NOSC) {
+ if (!IS_ENABLED(CONFIG_NVME_TARGET_TCP_TLS))
+ return NVME_AUTH_DHCHAP_FAILURE_CONCAT_MISMATCH;
+ /* Secure concatenation can only be enabled on the admin queue */
+ if (req->sq->qid)
+ return NVME_AUTH_DHCHAP_FAILURE_CONCAT_MISMATCH;
+ switch (data->sc_c) {
+ case NVME_AUTH_SECP_NEWTLSPSK:
+ if (nvmet_queue_tls_keyid(req->sq))
+ return NVME_AUTH_DHCHAP_FAILURE_CONCAT_MISMATCH;
+ break;
+ case NVME_AUTH_SECP_REPLACETLSPSK:
+ if (!nvmet_queue_tls_keyid(req->sq))
+ return NVME_AUTH_DHCHAP_FAILURE_CONCAT_MISMATCH;
+ break;
+ default:
+ return NVME_AUTH_DHCHAP_FAILURE_CONCAT_MISMATCH;
+ }
+ ctrl->concat = true;
+ }

if (data->napd != 1)
return NVME_AUTH_DHCHAP_FAILURE_HASH_UNUSABLE;
@@ -103,6 +121,12 @@ static u8 nvmet_auth_negotiate(struct nvmet_req *req, void *d)
nvme_auth_dhgroup_name(fallback_dhgid));
ctrl->dh_gid = fallback_dhgid;
}
+ if (ctrl->dh_gid == NVME_AUTH_DHGROUP_NULL && ctrl->concat) {
+ pr_debug("%s: ctrl %d qid %d: NULL DH group invalid "
+ "for secure channel concatenation\n", __func__,
+ ctrl->cntlid, req->sq->qid);
+ return NVME_AUTH_DHCHAP_FAILURE_CONCAT_MISMATCH;
+ }
pr_debug("%s: ctrl %d qid %d: selected DH group %s (%d)\n",
__func__, ctrl->cntlid, req->sq->qid,
nvme_auth_dhgroup_name(ctrl->dh_gid), ctrl->dh_gid);
@@ -148,12 +172,22 @@ static u8 nvmet_auth_reply(struct nvmet_req *req, void *d)
if (memcmp(data->rval, response, data->hl)) {
pr_info("ctrl %d qid %d host response mismatch\n",
ctrl->cntlid, req->sq->qid);
+ pr_debug("ctrl %d qid %d rval %*ph\n",
+ ctrl->cntlid, req->sq->qid, data->hl, data->rval);
+ pr_debug("ctrl %d qid %d response %*ph\n",
+ ctrl->cntlid, req->sq->qid, data->hl, response);
kfree(response);
return NVME_AUTH_DHCHAP_FAILURE_FAILED;
}
kfree(response);
pr_debug("%s: ctrl %d qid %d host authenticated\n",
__func__, ctrl->cntlid, req->sq->qid);
+ if (!data->cvalid && ctrl->concat) {
+ pr_debug("%s: ctrl %d qid %d invalid challenge\n",
+ __func__, ctrl->cntlid, req->sq->qid);
+ return NVME_AUTH_DHCHAP_FAILURE_FAILED;
+ }
+ req->sq->dhchap_s2 = le32_to_cpu(data->seqnum);
if (data->cvalid) {
req->sq->dhchap_c2 = kmemdup(data->rval + data->hl, data->hl,
GFP_KERNEL);
@@ -163,11 +197,23 @@ static u8 nvmet_auth_reply(struct nvmet_req *req, void *d)
pr_debug("%s: ctrl %d qid %d challenge %*ph\n",
__func__, ctrl->cntlid, req->sq->qid, data->hl,
req->sq->dhchap_c2);
- } else {
+ }
+ /*
+ * NVMe Base Spec 2.2 section 8.3.4.5.4: DH-HMAC-CHAP_Reply message
+ * Sequence Number (SEQNUM): [ .. ]
+ * The value 0h is used to indicate that bidirectional authentication
+ * is not performed, but a challenge value C2 is carried in order to
+ * generate a pre-shared key (PSK) for subsequent establishment of a
+ * secure channel.
+ */
+ if (req->sq->dhchap_s2 == 0) {
+ if (ctrl->concat)
+ nvmet_auth_insert_psk(req->sq);
req->sq->authenticated = true;
+ kfree(req->sq->dhchap_c2);
req->sq->dhchap_c2 = NULL;
- }
- req->sq->dhchap_s2 = le32_to_cpu(data->seqnum);
+ } else if (!data->cvalid)
+ req->sq->authenticated = true;

return 0;
}
@@ -303,6 +349,8 @@ void nvmet_execute_auth_send(struct nvmet_req *req)
}
goto done_kfree;
case NVME_AUTH_DHCHAP_MESSAGE_SUCCESS2:
+ if (ctrl->concat)
+ nvmet_auth_insert_psk(req->sq);
req->sq->authenticated = true;
pr_debug("%s: ctrl %d qid %d ctrl authenticated\n",
__func__, ctrl->cntlid, req->sq->qid);
diff --git a/drivers/nvme/target/fabrics-cmd.c b/drivers/nvme/target/fabrics-cmd.c
index 899aa011936e..9c01a4b6e543 100644
--- a/drivers/nvme/target/fabrics-cmd.c
+++ b/drivers/nvme/target/fabrics-cmd.c
@@ -236,8 +236,22 @@ static u16 nvmet_install_queue(struct nvmet_ctrl *ctrl, struct nvmet_req *req)

static u32 nvmet_connect_result(struct nvmet_ctrl *ctrl, struct nvmet_sq *sq)
{
- bool needs_auth = nvmet_has_auth(ctrl);
+ bool needs_auth = nvmet_has_auth(ctrl, sq);
+ key_serial_t keyid = nvmet_queue_tls_keyid(sq);

+ /* Do not authenticate I/O queues for secure concatenation */
+ if (ctrl->concat && sq->qid)
+ needs_auth = false;
+
+ if (keyid)
+ pr_debug("%s: ctrl %d qid %d should %sauthenticate, tls psk %08x\n",
+ __func__, ctrl->cntlid, sq->qid,
+ needs_auth ? "" : "not ", keyid);
+ else
+ pr_debug("%s: ctrl %d qid %d should %sauthenticate%s\n",
+ __func__, ctrl->cntlid, sq->qid,
+ needs_auth ? "" : "not ",
+ ctrl->concat ? ", secure concatenation" : "");
return (u32)ctrl->cntlid |
(needs_auth ? NVME_CONNECT_AUTHREQ_ATR : 0);
}
diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index 6afe3b4763d5..7401d59f26df 100644
--- a/drivers/nvme/target/nvmet.h
+++ b/drivers/nvme/target/nvmet.h
@@ -157,6 +157,9 @@ struct nvmet_sq {
u32 dhchap_s2;
u8 *dhchap_skey;
int dhchap_skey_len;
+#endif
+#ifdef CONFIG_NVME_TARGET_TCP_TLS
+ struct key *tls_key;
#endif
struct completion free_done;
struct completion confirm_done;
@@ -282,6 +285,7 @@ struct nvmet_ctrl {
u64 err_counter;
struct nvme_error_slot slots[NVMET_ERROR_LOG_SLOTS];
bool pi_support;
+ bool concat;
#ifdef CONFIG_NVME_TARGET_AUTH
struct nvme_dhchap_key *host_key;
struct nvme_dhchap_key *ctrl_key;
@@ -290,6 +294,9 @@ struct nvmet_ctrl {
u8 dh_gid;
u8 *dh_key;
size_t dh_keysize;
+#endif
+#ifdef CONFIG_NVME_TARGET_TCP_TLS
+ struct key *tls_key;
#endif
struct nvmet_pr_log_mgr pr_log_mgr;
};
@@ -846,6 +853,22 @@ static inline void nvmet_req_bio_put(struct nvmet_req *req, struct bio *bio)
bio_put(bio);
}

+#ifdef CONFIG_NVME_TARGET_TCP_TLS
+static inline key_serial_t nvmet_queue_tls_keyid(struct nvmet_sq *sq)
+{
+ return sq->tls_key ? key_serial(sq->tls_key) : 0;
+}
+static inline void nvmet_sq_put_tls_key(struct nvmet_sq *sq)
+{
+ if (sq->tls_key) {
+ key_put(sq->tls_key);
+ sq->tls_key = NULL;
+ }
+}
+#else
+static inline key_serial_t nvmet_queue_tls_keyid(struct nvmet_sq *sq) { return 0; }
+static inline void nvmet_sq_put_tls_key(struct nvmet_sq *sq) {}
+#endif
#ifdef CONFIG_NVME_TARGET_AUTH
u32 nvmet_auth_send_data_len(struct nvmet_req *req);
void nvmet_execute_auth_send(struct nvmet_req *req);
@@ -864,14 +887,15 @@ int nvmet_auth_host_hash(struct nvmet_req *req, u8 *response,
unsigned int hash_len);
int nvmet_auth_ctrl_hash(struct nvmet_req *req, u8 *response,
unsigned int hash_len);
-static inline bool nvmet_has_auth(struct nvmet_ctrl *ctrl)
+static inline bool nvmet_has_auth(struct nvmet_ctrl *ctrl, struct nvmet_sq *sq)
{
- return ctrl->host_key != NULL;
+ return ctrl->host_key != NULL && !nvmet_queue_tls_keyid(sq);
}
int nvmet_auth_ctrl_exponential(struct nvmet_req *req,
u8 *buf, int buf_size);
int nvmet_auth_ctrl_sesskey(struct nvmet_req *req,
u8 *buf, int buf_size);
+void nvmet_auth_insert_psk(struct nvmet_sq *sq);
#else
static inline u8 nvmet_setup_auth(struct nvmet_ctrl *ctrl,
struct nvmet_sq *sq)
@@ -887,11 +911,13 @@ static inline bool nvmet_check_auth_status(struct nvmet_req *req)
{
return true;
}
-static inline bool nvmet_has_auth(struct nvmet_ctrl *ctrl)
+static inline bool nvmet_has_auth(struct nvmet_ctrl *ctrl,
+ struct nvmet_sq *sq)
{
return false;
}
static inline const char *nvmet_dhchap_dhgroup_name(u8 dhgid) { return NULL; }
+static inline void nvmet_auth_insert_psk(struct nvmet_sq *sq) {};
#endif

int nvmet_pr_init_ns(struct nvmet_ns *ns);
diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c
index fa59a7996efa..9cf97433b0b6 100644
--- a/drivers/nvme/target/tcp.c
+++ b/drivers/nvme/target/tcp.c
@@ -1072,10 +1072,11 @@ static int nvmet_tcp_done_recv_pdu(struct nvmet_tcp_queue *queue)

if (unlikely(!nvmet_req_init(req, &queue->nvme_cq,
&queue->nvme_sq, &nvmet_tcp_ops))) {
- pr_err("failed cmd %p id %d opcode %d, data_len: %d\n",
+ pr_err("failed cmd %p id %d opcode %d, data_len: %d, status: %04x\n",
req->cmd, req->cmd->common.command_id,
req->cmd->common.opcode,
- le32_to_cpu(req->cmd->common.dptr.sgl.length));
+ le32_to_cpu(req->cmd->common.dptr.sgl.length),
+ le16_to_cpu(req->cqe->status));

nvmet_tcp_handle_req_failure(queue, queue->cmd, req);
return 0;
@@ -1601,6 +1602,7 @@ static void nvmet_tcp_release_queue_work(struct work_struct *w)
/* stop accepting incoming data */
queue->rcv_state = NVMET_TCP_RECV_ERR;

+ nvmet_sq_put_tls_key(&queue->nvme_sq);
nvmet_tcp_uninit_data_in_cmds(queue);
nvmet_sq_destroy(&queue->nvme_sq);
cancel_work_sync(&queue->io_work);
@@ -1786,6 +1788,27 @@ static int nvmet_tcp_try_peek_pdu(struct nvmet_tcp_queue *queue)
return 0;
}

+static int nvmet_tcp_tls_key_lookup(struct nvmet_tcp_queue *queue,
+ key_serial_t peerid)
+{
+ struct key *tls_key = nvme_tls_key_lookup(peerid);
+ int status = 0;
+
+ if (IS_ERR(tls_key)) {
+ pr_warn("%s: queue %d failed to lookup key %x\n",
+ __func__, queue->idx, peerid);
+ spin_lock_bh(&queue->state_lock);
+ queue->state = NVMET_TCP_Q_FAILED;
+ spin_unlock_bh(&queue->state_lock);
+ status = PTR_ERR(tls_key);
+ } else {
+ pr_debug("%s: queue %d using TLS PSK %x\n",
+ __func__, queue->idx, peerid);
+ queue->nvme_sq.tls_key = tls_key;
+ }
+ return status;
+}
+
static void nvmet_tcp_tls_handshake_done(void *data, int status,
key_serial_t peerid)
{
@@ -1806,6 +1829,10 @@ static void nvmet_tcp_tls_handshake_done(void *data, int status,
spin_unlock_bh(&queue->state_lock);

cancel_delayed_work_sync(&queue->tls_handshake_tmo_work);
+
+ if (!status)
+ status = nvmet_tcp_tls_key_lookup(queue, peerid);
+
if (status)
nvmet_tcp_schedule_release_queue(queue);
else
--
2.35.3