[PATCH 07/10] nvme-tcp: request secure channel concatenation

Hannes Reinecke
2024-12-02T14:30:25Z

Add a fabrics option 'concat' to request 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>
---
drivers/nvme/host/auth.c | 113 +++++++++++++++++++++++++++++++++++-
drivers/nvme/host/fabrics.c | 34 ++++++++++-
drivers/nvme/host/fabrics.h | 3 +
drivers/nvme/host/nvme.h | 2 +
drivers/nvme/host/sysfs.c | 4 +-
drivers/nvme/host/tcp.c | 57 ++++++++++++++++--
include/linux/nvme.h | 7 +++
7 files changed, 206 insertions(+), 14 deletions(-)

diff --git a/drivers/nvme/host/auth.c b/drivers/nvme/host/auth.c
index 371e14f0a203..f23a4c6326d7 100644
--- a/drivers/nvme/host/auth.c
+++ b/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 +132,12 @@ 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)
+ data->sc_c = NVME_AUTH_SECP_NOSC;
+ else if (ctrl->opts->tls_key)
+ data->sc_c = NVME_AUTH_SECP_REPLACETLSPSK;
+ else
+ data->sc_c = NVME_AUTH_SECP_NEWTLSPSK;
data->napd = 1;
data->auth_protocol[0].dhchap.authid = NVME_AUTH_DHCHAP_AUTH_ID;
data->auth_protocol[0].dhchap.halen = 3;
@@ -311,8 +317,9 @@ 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 +329,10 @@ 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 +687,90 @@ 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 +927,13 @@ 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 +1013,12 @@ 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);
diff --git a/drivers/nvme/host/fabrics.c b/drivers/nvme/host/fabrics.c
index 432efcbf9e2f..93e9041b9657 100644
--- a/drivers/nvme/host/fabrics.c
+++ b/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)) {
diff --git a/drivers/nvme/host/fabrics.h b/drivers/nvme/host/fabrics.h
index 21d75dc4a3a0..9cf5b020adba 100644
--- a/drivers/nvme/host/fabrics.h
+++ b/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;
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 313a4f978a2c..4c735b88b434 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -1132,6 +1132,7 @@ 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)
{
@@ -1154,6 +1155,7 @@ 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 void nvme_auth_revoke_tls_key(struct nvme_ctrl *ctrl) {};
#endif

u32 nvme_command_effects(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
diff --git a/drivers/nvme/host/sysfs.c b/drivers/nvme/host/sysfs.c
index b68a9e5f1ea3..efb35eef1915 100644
--- a/drivers/nvme/host/sysfs.c
+++ b/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)
diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index b5e11a0f7ba8..9268c6f2c99f 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -232,7 +232,7 @@ static inline bool nvme_tcp_tls_configured(struct nvme_ctrl *ctrl)
if (!IS_ENABLED(CONFIG_NVME_TCP_TLS))
return 0;

- return ctrl->opts->tls;
+ return ctrl->opts->tls || ctrl->opts->concat;
}

static inline struct blk_mq_tags *nvme_tcp_tagset(struct nvme_tcp_queue *queue)
@@ -1947,7 +1947,7 @@ static int nvme_tcp_alloc_admin_queue(struct nvme_ctrl *ctrl)
if (nvme_tcp_tls_configured(ctrl)) {
if (ctrl->opts->tls_key)
pskid = key_serial(ctrl->opts->tls_key);
- else {
+ else if (ctrl->opts->tls) {
pskid = nvme_tls_psk_default(ctrl->opts->keyring,
ctrl->opts->host->nqn,
ctrl->opts->subsysnqn);
@@ -1977,9 +1977,25 @@ static int __nvme_tcp_alloc_io_queues(struct nvme_ctrl *ctrl)
{
int i, ret;

- if (nvme_tcp_tls_configured(ctrl) && !ctrl->tls_pskid) {
- dev_err(ctrl->device, "no PSK negotiated\n");
- return -ENOKEY;
+ if (nvme_tcp_tls_configured(ctrl)) {
+ if (ctrl->opts->concat) {
+ /*
+ * The generated PSK is stored in the
+ * fabric options
+ */
+ if (!ctrl->opts->tls_key) {
+ dev_err(ctrl->device, "no PSK generated\n");
+ return -ENOKEY;
+ }
+ if (ctrl->tls_pskid &&
+ ctrl->tls_pskid != key_serial(ctrl->opts->tls_key)) {
+ dev_err(ctrl->device, "Stale PSK id %08x\n", ctrl->tls_pskid);
+ ctrl->tls_pskid = 0;
+ }
+ } else if (!ctrl->tls_pskid) {
+ dev_err(ctrl->device, "no PSK negotiated\n");
+ return -ENOKEY;
+ }
}

for (i = 1; i < ctrl->queue_count; i++) {
@@ -2210,6 +2226,31 @@ static void nvme_tcp_reconnect_or_remove(struct nvme_ctrl *ctrl,
}
}

+/*
+ * The TLS key is set by secure concatenation after negotiation
+ * has been completed on the admin queue. We need to revoke the
+ * key when:
+ * - concatenation is enabled
+ * (otherwise it's a static key set by the user)
+ * and
+ * - the generated key is present in ctrl->tls_key
+ * (otherwise there's nothing to revoke)
+ * and
+ * - a valid PSK key ID has been set in ctrl->tls_pskid
+ * (otherwise TLS negotiation has not run).
+ *
+ * We cannot always revoke the key, as we're calling
+ * nvme_tcp_alloc_admin_queue() twice during secure
+ * concatenation, once on a 'normal' connection to run
+ * the DH-HMAC-CHAP negotiation (which generates the key,
+ * so it _must not_ be set), and once after the negotiation
+ * (which uses the key, so it _must_ be set).
+ */
+static bool nvme_tcp_key_revoke_needed(struct nvme_ctrl *ctrl)
+{
+ return ctrl->opts->concat && ctrl->opts->tls_key && ctrl->tls_pskid;
+}
+
static int nvme_tcp_setup_ctrl(struct nvme_ctrl *ctrl, bool new)
{
struct nvmf_ctrl_options *opts = ctrl->opts;
@@ -2313,6 +2354,8 @@ static void nvme_tcp_error_recovery_work(struct work_struct *work)
struct nvme_tcp_ctrl, err_work);
struct nvme_ctrl *ctrl = &tcp_ctrl->ctrl;

+ if (nvme_tcp_key_revoke_needed(ctrl))
+ nvme_auth_revoke_tls_key(ctrl);
nvme_stop_keep_alive(ctrl);
flush_work(&ctrl->async_event_work);
nvme_tcp_teardown_io_queues(ctrl, false);
@@ -2353,6 +2396,8 @@ static void nvme_reset_ctrl_work(struct work_struct *work)
container_of(work, struct nvme_ctrl, reset_work);
int ret;

+ if (nvme_tcp_key_revoke_needed(ctrl))
+ nvme_auth_revoke_tls_key(ctrl);
nvme_stop_ctrl(ctrl);
nvme_tcp_teardown_ctrl(ctrl, false);

@@ -2848,7 +2893,7 @@ static struct nvmf_transport_ops nvme_tcp_transport = {
NVMF_OPT_HDR_DIGEST | NVMF_OPT_DATA_DIGEST |
NVMF_OPT_NR_WRITE_QUEUES | NVMF_OPT_NR_POLL_QUEUES |
NVMF_OPT_TOS | NVMF_OPT_HOST_IFACE | NVMF_OPT_TLS |
- NVMF_OPT_KEYRING | NVMF_OPT_TLS_KEY,
+ NVMF_OPT_KEYRING | NVMF_OPT_TLS_KEY | NVMF_OPT_CONCAT,
.create_ctrl = nvme_tcp_create_ctrl,
};

diff --git a/include/linux/nvme.h b/include/linux/nvme.h
index b58d9405d65e..fe8858d19813 100644
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -1678,6 +1678,13 @@ enum {
NVME_AUTH_DHGROUP_INVALID = 0xff,
};

+enum {
+ NVME_AUTH_SECP_NOSC = 0x00,
+ NVME_AUTH_SECP_SC = 0x01,
+ NVME_AUTH_SECP_NEWTLSPSK = 0x02,
+ NVME_AUTH_SECP_REPLACETLSPSK = 0x03,
+};
+
union nvmf_auth_protocol {
struct nvmf_auth_dhchap_protocol_descriptor dhchap;
};
--
2.35.3