Re: [PATCH 13/14] nvmet-tcp: enable TLS handshake upcall

Hannes Reinecke
2023-08-07T09:16:02Z

On 8/7/23 10:51, Sagi Grimberg wrote:
>
>
> On 8/3/23 13:51, Hannes Reinecke wrote:
>> Add functions to start the TLS handshake upcall when
>> the TCP TSAS sectype is set to 'tls1.3' and add a config
>> option NVME_TARGET_TCP_TLS.
>>
>> Signed-off-by: Hannes Reincke <hare@suse.de>
>> ---
>>   drivers/nvme/target/Kconfig    |  14 ++++
>>   drivers/nvme/target/configfs.c |  63 +++++++++++++++-
>>   drivers/nvme/target/nvmet.h    |   1 +
>>   drivers/nvme/target/tcp.c      | 133 +++++++++++++++++++++++++++++++--
>>   4 files changed, 203 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/nvme/target/Kconfig b/drivers/nvme/target/Kconfig
>> index 79fc64035ee3..15af2b4341f6 100644
>> --- a/drivers/nvme/target/Kconfig
>> +++ b/drivers/nvme/target/Kconfig
>> @@ -84,6 +84,20 @@ config NVME_TARGET_TCP
>>         If unsure, say N.
>> +config NVME_TARGET_TCP_TLS
>> +    bool "NVMe over Fabrics TCP target TLS encryption support"
>> +    depends on NVME_TARGET_TCP
>> +    select NVME_COMMON
>> +    select NVME_KEYRING
>> +    select NET_HANDSHAKE
>> +    help
>> +      Enables TLS encryption for the NVMe TCP target using the
>> netlink handshake API.
>> +
>> +      The TLS handshake daemon is availble at
>> +      https://github.com/oracle/ktls-utils.
>> +
>> +      If unsure, say N.
>> +
>>   config NVME_TARGET_AUTH
>>       bool "NVMe over Fabrics In-band Authentication support"
>>       depends on NVME_TARGET
>> diff --git a/drivers/nvme/target/configfs.c
>> b/drivers/nvme/target/configfs.c
>> index 7f826ac8b75c..49b407702ad5 100644
>> --- a/drivers/nvme/target/configfs.c
>> +++ b/drivers/nvme/target/configfs.c
>> @@ -15,6 +15,7 @@
>>   #ifdef CONFIG_NVME_TARGET_AUTH
>>   #include <linux/nvme-auth.h>
>>   #endif
>> +#include <linux/nvme-keyring.h>
>>   #include <crypto/hash.h>
>>   #include <crypto/kpp.h>
>> @@ -159,10 +160,15 @@ static const struct nvmet_type_name_map
>> nvmet_addr_treq[] = {
>>       { NVMF_TREQ_NOT_REQUIRED,    "not required" },
>>   };
>> +static inline u8 nvmet_port_treq(struct nvmet_port *port)
>> +{
>> +    return (port->disc_addr.treq & NVME_TREQ_SECURE_CHANNEL_MASK);
>> +}
>> +
>>   static ssize_t nvmet_addr_treq_show(struct config_item *item, char
>> *page)
>>   {
>> -    u8 treq = to_nvmet_port(item)->disc_addr.treq &
>> -        NVME_TREQ_SECURE_CHANNEL_MASK;
>> +    struct nvmet_port *port = to_nvmet_port(item);
>> +    u8 treq = nvmet_port_treq(port);
>>       int i;
>>       for (i = 0; i < ARRAY_SIZE(nvmet_addr_treq); i++) {
>> @@ -174,11 +180,16 @@ static ssize_t nvmet_addr_treq_show(struct
>> config_item *item, char *page)
>>       return snprintf(page, PAGE_SIZE, "\n");
>>   }
>> +static inline u8 nvmet_port_treq_mask(struct nvmet_port *port)
>> +{
>> +    return (port->disc_addr.treq & ~NVME_TREQ_SECURE_CHANNEL_MASK);
>> +}
>> +
>>   static ssize_t nvmet_addr_treq_store(struct config_item *item,
>>           const char *page, size_t count)
>>   {
>>       struct nvmet_port *port = to_nvmet_port(item);
>> -    u8 treq = port->disc_addr.treq & ~NVME_TREQ_SECURE_CHANNEL_MASK;
>> +    u8 treq = nvmet_port_treq_mask(port);
>>       int i;
>>       if (nvmet_is_port_enabled(port, __func__))
>> @@ -193,6 +204,23 @@ static ssize_t nvmet_addr_treq_store(struct
>> config_item *item,
>>       return -EINVAL;
>>   found:
>> +    if (port->disc_addr.trtype == NVMF_TRTYPE_TCP) {
>> +        if (!IS_ENABLED(CONFIG_NVME_TARGET_TCP_TLS)) {
>> +            pr_err("TLS is not supported\n");
>> +            return -EINVAL;
>> +        }
>> +        if (!port->keyring) {
>> +            pr_err("TLS keyring not configured\n");
>> +            return -EINVAL;
>> +        }
>> +        if (port->disc_addr.tsas.tcp.sectype !=
>> NVMF_TCP_SECTYPE_TLS13) {
>> +            pr_warn("cannot change TREQ when TLS is not enabled\n");
>> +            return -EINVAL;
>> +        } else if (nvmet_addr_treq[i].type == NVMF_TREQ_NOT_SPECIFIED) {
>> +            pr_warn("cannot set TREQ to 'not specified' when TLS is
>> enabled\n");
>> +            return -EINVAL;
>> +        }
>> +    }
>>       treq |= nvmet_addr_treq[i].type;
>>       port->disc_addr.treq = treq;
>>       return count;
>> @@ -371,6 +399,7 @@ static ssize_t nvmet_addr_tsas_store(struct
>> config_item *item,
>>           const char *page, size_t count)
>>   {
>>       struct nvmet_port *port = to_nvmet_port(item);
>> +    u8 treq = nvmet_port_treq_mask(port);
>>       int i;
>>       if (nvmet_is_port_enabled(port, __func__))
>> @@ -379,6 +408,15 @@ static ssize_t nvmet_addr_tsas_store(struct
>> config_item *item,
>>       if (port->disc_addr.trtype != NVMF_TRTYPE_TCP)
>>           return -EINVAL;
>> +    if (!IS_ENABLED(CONFIG_NVME_TARGET_TCP_TLS)) {
>> +        pr_err("TLS is not supported\n");
>> +        return -EINVAL;
>> +    }
>> +    if (!port->keyring) {
>> +        pr_err("TLS keyring not configured\n");
>> +        return -EINVAL;
>> +    }
>> +
>>       for (i = 0; i < ARRAY_SIZE(nvmet_addr_tsas_tcp); i++) {
>>           if (sysfs_streq(page, nvmet_addr_tsas_tcp[i].name))
>>               goto found;
>> @@ -389,6 +427,16 @@ static ssize_t nvmet_addr_tsas_store(struct
>> config_item *item,
>>   found:
>>       nvmet_port_init_tsas_tcp(port, nvmet_addr_tsas_tcp[i].type);
>> +    if (nvmet_addr_tsas_tcp[i].type == NVMF_TCP_SECTYPE_TLS13) {
>> +        if (nvmet_port_treq(port) == NVMF_TREQ_NOT_SPECIFIED)
>> +            treq |= NVMF_TREQ_REQUIRED;
>> +        else
>> +            treq |= nvmet_port_treq(port);
>> +    } else {
>> +        /* Set to 'not specified' if TLS is not enabled */
>> +        treq |= NVMF_TREQ_NOT_SPECIFIED;
>> +    }
>> +    port->disc_addr.treq = treq;
>>       return count;
>>   }
>
> Can the treq/tsas be split from the actual nvmet-tcp upcall addition?
>
I guess it can; it's just that it doesn't make any sense if we don't
have the TLS upcall implemented.

>> @@ -1795,6 +1843,7 @@ static void nvmet_port_release(struct
>> config_item *item)
>>       flush_workqueue(nvmet_wq);
>>       list_del(&port->global_entry);
>> +    key_put(port->keyring);
>>       kfree(port->ana_state);
>>       kfree(port);
>>   }
>> @@ -1844,6 +1893,14 @@ static struct config_group
>> *nvmet_ports_make(struct config_group *group,
>>           return ERR_PTR(-ENOMEM);
>>       }
>> +    if (nvme_keyring_id()) {
>> +        port->keyring = key_lookup(nvme_keyring_id());
>> +        if (IS_ERR(port->keyring)) {
>> +            pr_warn("NVMe keyring not available, disabling TLS\n");
>> +            port->keyring = NULL;
>> +        }
>> +    }
>> +
>
> Nice.
>
>>       for (i = 1; i <= NVMET_MAX_ANAGRPS; i++) {
>>           if (i == NVMET_DEFAULT_ANA_GRPID)
>>               port->ana_state[1] = NVME_ANA_OPTIMIZED;
>> diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
>> index 8cfd60f3b564..7f9ae53c1df5 100644
>> --- a/drivers/nvme/target/nvmet.h
>> +++ b/drivers/nvme/target/nvmet.h
>> @@ -158,6 +158,7 @@ struct nvmet_port {
>>       struct config_group        ana_groups_group;
>>       struct nvmet_ana_group        ana_default_group;
>>       enum nvme_ana_state        *ana_state;
>> +    struct key            *keyring;
>>       void                *priv;
>>       bool                enabled;
>>       int                inline_data_size;
>> diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c
>> index fdc351f591a4..7279c994abd6 100644
>> --- a/drivers/nvme/target/tcp.c
>> +++ b/drivers/nvme/target/tcp.c
>> @@ -8,9 +8,13 @@
>>   #include <linux/init.h>
>>   #include <linux/slab.h>
>>   #include <linux/err.h>
>> +#include <linux/key.h>
>>   #include <linux/nvme-tcp.h>
>> +#include <linux/nvme-keyring.h>
>>   #include <net/sock.h>
>>   #include <net/tcp.h>
>> +#include <net/tls.h>
>> +#include <net/handshake.h>
>>   #include <linux/inet.h>
>>   #include <linux/llist.h>
>>   #include <crypto/hash.h>
>> @@ -66,6 +70,16 @@ device_param_cb(idle_poll_period_usecs,
>> &set_param_ops,
>>   MODULE_PARM_DESC(idle_poll_period_usecs,
>>           "nvmet tcp io_work poll till idle time period in usecs:
>> Default 0");
>> +#ifdef CONFIG_NVME_TARGET_TCP_TLS
>> +/*
>> + * TLS handshake timeout
>> + */
>> +static int tls_handshake_timeout = 30;
>> +module_param(tls_handshake_timeout, int, 0644);
>> +MODULE_PARM_DESC(tls_handshake_timeout,
>> +         "nvme TLS handshake timeout in seconds (default 30)");
>> +#endif
>
> On the host it is 10 and here 30? what is the source of the assymmetry?
>
Hmm. Looks like an oversight. Will be aligning them.

>> +
>>   #define NVMET_TCP_RECV_BUDGET        8
>>   #define NVMET_TCP_SEND_BUDGET        8
>>   #define NVMET_TCP_IO_WORK_BUDGET    64
>> @@ -122,6 +136,7 @@ struct nvmet_tcp_cmd {
>>   enum nvmet_tcp_queue_state {
>>       NVMET_TCP_Q_CONNECTING,
>> +    NVMET_TCP_Q_TLS_HANDSHAKE,
>>       NVMET_TCP_Q_LIVE,
>>       NVMET_TCP_Q_DISCONNECTING,
>>   };
>> @@ -154,6 +169,8 @@ struct nvmet_tcp_queue {
>>       bool            data_digest;
>>       struct ahash_request    *snd_hash;
>>       struct ahash_request    *rcv_hash;
>> +    key_serial_t        tls_pskid;
>> +    struct delayed_work    tls_handshake_work;
>>       unsigned long           poll_end;
>> @@ -1285,12 +1302,12 @@ static int nvmet_tcp_try_recv(struct
>> nvmet_tcp_queue *queue,
>>   static void nvmet_tcp_schedule_release_queue(struct nvmet_tcp_queue
>> *queue)
>>   {
>> -    spin_lock(&queue->state_lock);
>> +    spin_lock_irq(&queue->state_lock);
>
> Where is this lock taken in irq context that needs disabling irq?
>
Let me check; might be that it got solved with the workqueue fixes which
went in lately.

>>       if (queue->state != NVMET_TCP_Q_DISCONNECTING) {
>>           queue->state = NVMET_TCP_Q_DISCONNECTING;
>>           queue_work(nvmet_wq, &queue->release_work);
>>       }
>> -    spin_unlock(&queue->state_lock);
>> +    spin_unlock_irq(&queue->state_lock);
>>   }
>>   static inline void nvmet_tcp_arm_queue_deadline(struct
>> nvmet_tcp_queue *queue)
>> @@ -1512,8 +1529,12 @@ static void nvmet_tcp_data_ready(struct sock *sk)
>>       read_lock_bh(&sk->sk_callback_lock);
>>       queue = sk->sk_user_data;
>> -    if (likely(queue))
>> -        queue_work_on(queue_cpu(queue), nvmet_tcp_wq, &queue->io_work);
>> +    if (queue->data_ready)
>> +        queue->data_ready(sk);
>> +    if (likely(queue) &&
>> +        queue->state != NVMET_TCP_Q_TLS_HANDSHAKE)
>> +        queue_work_on(queue_cpu(queue), nvmet_tcp_wq,
>> +                  &queue->io_work);
>>       read_unlock_bh(&sk->sk_callback_lock);
>>   }
>> @@ -1621,6 +1642,85 @@ static int nvmet_tcp_set_queue_sock(struct
>> nvmet_tcp_queue *queue)
>>       return ret;
>>   }
>> +#ifdef CONFIG_NVME_TARGET_TCP_TLS
>> +static void nvmet_tcp_tls_queue_reset(struct nvmet_tcp_queue *queue)
>> +{
>> +    spin_lock_irq(&queue->state_lock);
>> +    if (queue->state != NVMET_TCP_Q_TLS_HANDSHAKE) {
>> +        pr_warn("queue %d: TLS handshake already completed\n",
>> +            queue->idx);
>> +        spin_unlock_irq(&queue->state_lock);
>> +        return;
>
> trigger fatal error here?
>
Good point.

>> +    }
>> +    queue->state = NVMET_TCP_Q_CONNECTING;
>> +    spin_unlock_irq(&queue->state_lock);
>> +
>> +    pr_debug("queue %d: resetting queue callbacks after TLS
>> handshake\n",
>> +         queue->idx);
>> +    /*
>> +     * Set callbacks after handshake; TLS implementation
>> +     * might have changed the socket callbacks.
>> +     */
>> +    nvmet_tcp_set_queue_sock(queue);
>> +}
>> +
>> +static void nvmet_tcp_tls_handshake_done(void *data, int status,
>> +                     key_serial_t peerid)
>
> lets call peerid psk_id throughout.
>
Okay.

>> +{
>> +    struct nvmet_tcp_queue *queue = data;
>> +
>> +    pr_debug("queue %d: TLS handshake done, key %x, status %d\n",
>> +         queue->idx, peerid, status);
>> +    if (!status) {
>> +        spin_lock_irq(&queue->state_lock);
>> +        queue->tls_pskid = peerid;
>> +        spin_unlock_irq(&queue->state_lock);
>> +    }
>> +    cancel_delayed_work_sync(&queue->tls_handshake_work);
>
> Hmm, the cancel_delayed_work_sync is scary.
>
> What happens if it ran and already scheduled a release (which
> already ran and completed)?
>
Well, we need to stop the timeout at some point; granted, for a failure
we can just flush the workqueue, but in the success case we need
terminate the workqueue.
And nvmet_tcp_schedule_release_queue() already checks for the queue
state, so we should be (reasonably) safe.

>> +    if (status)
>> +        nvmet_tcp_schedule_release_queue(queue);
>> +    else
>> +        nvmet_tcp_tls_queue_reset(queue);
>
> What I think you need is an atomic state that one or the
> other access, and then you are fine with a normal async
> cancel of the delayed_work.
>
Hmm. I'll have a look.

>> +}
>> +
>> +static void nvmet_tcp_tls_handshake_timeout_work(struct work_struct *w)
>> +{
>> +    struct nvmet_tcp_queue *queue = container_of(to_delayed_work(w),
>> +            struct nvmet_tcp_queue, tls_handshake_work);
>> +
>> +    pr_debug("queue %d: TLS handshake timeout\n", queue->idx);
>> +    nvmet_tcp_schedule_release_queue(queue);
>> +}
>> +
>> +static int nvmet_tcp_tls_handshake(struct nvmet_tcp_queue *queue)
>> +{
>> +    int ret = -EOPNOTSUPP;
>> +    struct tls_handshake_args args;
>> +
>> +    if (queue->state != NVMET_TCP_Q_TLS_HANDSHAKE) {
>> +        pr_warn("cannot start TLS in state %d\n", queue->state);
>> +        return -EINVAL;
>> +    }
>> +
>> +    pr_debug("queue %d: TLS ServerHello\n", queue->idx);
>> +    memset(&args, 0, sizeof(args));
>> +    args.ta_sock = queue->sock;
>> +    args.ta_done = nvmet_tcp_tls_handshake_done;
>> +    args.ta_data = queue;
>> +    args.ta_keyring = key_serial(queue->port->nport->keyring);
>> +    args.ta_timeout_ms = tls_handshake_timeout * 2 * 1024;
>
> * 2 * 1024 ? I didn't know we have 2048 ms in a second...
>
The '_ms' bit is just an indicator of the unit, not the value.
We don't have an 'args.ta_timeout_sec' ...

>> +
>> +    ret = tls_server_hello_psk(&args, GFP_KERNEL);
>> +    if (ret) {
>> +        pr_err("failed to start TLS, err=%d\n", ret);
>> +    } else {
>> +        queue_delayed_work(nvmet_wq, &queue->tls_handshake_work,
>> +                   tls_handshake_timeout * HZ);
>> +    }
>> +    return ret;
>> +}
>> +#endif
>> +
>>   static void nvmet_tcp_alloc_queue(struct nvmet_tcp_port *port,
>>           struct socket *newsock)
>>   {
>> @@ -1638,7 +1738,11 @@ static void nvmet_tcp_alloc_queue(struct
>> nvmet_tcp_port *port,
>>       queue->port = port;
>>       queue->nr_cmds = 0;
>>       spin_lock_init(&queue->state_lock);
>> -    queue->state = NVMET_TCP_Q_CONNECTING;
>> +    if (queue->port->nport->disc_addr.tsas.tcp.sectype ==
>> +        NVMF_TCP_SECTYPE_TLS13)
>> +        queue->state = NVMET_TCP_Q_TLS_HANDSHAKE;
>> +    else
>> +        queue->state = NVMET_TCP_Q_CONNECTING;
>>       INIT_LIST_HEAD(&queue->free_list);
>>       init_llist_head(&queue->resp_list);
>>       INIT_LIST_HEAD(&queue->resp_send_list);
>> @@ -1669,6 +1773,25 @@ static void nvmet_tcp_alloc_queue(struct
>> nvmet_tcp_port *port,
>>       list_add_tail(&queue->queue_list, &nvmet_tcp_queue_list);
>>       mutex_unlock(&nvmet_tcp_queue_mutex);
>> +#ifdef CONFIG_NVME_TARGET_TCP_TLS
>
> maybe the ifdef can be avoided with stubs?
>
Lemme check.

Cheers,

Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@suse.de +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
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