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Message-ID: <1eca42a4-ee8e-dff3-adb0-0f4799e4f96f@suse.de>
Date: Tue, 15 Aug 2023 09:20:12 +0200
From: Hannes Reinecke <hare@...e.de>
To: Sagi Grimberg <sagi@...mberg.me>, Christoph Hellwig <hch@....de>
Cc: Keith Busch <kbusch@...nel.org>, linux-nvme@...ts.infradead.org,
Jakub Kicinski <kuba@...nel.org>, Eric Dumazet <edumazet@...gle.com>,
Paolo Abeni <pabeni@...hat.com>, netdev@...r.kernel.org
Subject: Re: [PATCH 15/17] nvmet-tcp: enable TLS handshake upcall
On 8/15/23 09:01, Sagi Grimberg wrote:
>
>>>>>> @@ -1864,6 +1877,14 @@ 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;
>>>>>
>>>>> why setting this to NULL?
>>>>>
>>>> It's check when changing TSAS; we can only enable TLS if the nvme
>>>> keyring is available.
>>>
>>> ok
>>>
>>>>
>>>>>> + }
>>>>>> + }
>>>>>> +
>>>>>> 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 f19ea9d923fd..77fa339008e1 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 = 10;
>>>>>> +module_param(tls_handshake_timeout, int, 0644);
>>>>>> +MODULE_PARM_DESC(tls_handshake_timeout,
>>>>>> + "nvme TLS handshake timeout in seconds (default 10)");
>>>>>> +#endif
>>>>>> +
>>>>>> #define NVMET_TCP_RECV_BUDGET 8
>>>>>> #define NVMET_TCP_SEND_BUDGET 8
>>>>>> #define NVMET_TCP_IO_WORK_BUDGET 64
>>>>>> @@ -122,11 +136,13 @@ 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,
>>>>>> };
>>>>>> struct nvmet_tcp_queue {
>>>>>> + struct kref kref;
>>>>>
>>>>> Why is kref the first member of the struct?
>>>>>
>>>> Habit.
>>>> I don't mind where it'll end up.
>>>
>>> Move it to the back together with the tls section.
>>>
>>>>
>>>>>> struct socket *sock;
>>>>>> struct nvmet_tcp_port *port;
>>>>>> struct work_struct io_work;
>>>>>> @@ -155,6 +171,10 @@ struct nvmet_tcp_queue {
>>>>>> struct ahash_request *snd_hash;
>>>>>> struct ahash_request *rcv_hash;
>>>>>> + /* TLS state */
>>>>>> + key_serial_t tls_pskid;
>>>>>> + struct delayed_work tls_handshake_work;
>>>>>> +
>>>>>> unsigned long poll_end;
>>>>>> spinlock_t state_lock;
>>>>>> @@ -1283,12 +1303,21 @@ static int nvmet_tcp_try_recv(struct
>>>>>> nvmet_tcp_queue *queue,
>>>>>> return ret;
>>>>>> }
>>>>>> +static void nvmet_tcp_release_queue(struct kref *kref)
>>>>>> +{
>>>>>> + struct nvmet_tcp_queue *queue =
>>>>>> + container_of(kref, struct nvmet_tcp_queue, kref);
>>>>>> +
>>>>>> + WARN_ON(queue->state != NVMET_TCP_Q_DISCONNECTING);
>>>>>> + queue_work(nvmet_wq, &queue->release_work);
>>>>>> +}
>>>>>> +
>>>>>> static void nvmet_tcp_schedule_release_queue(struct
>>>>>> nvmet_tcp_queue *queue)
>>>>>> {
>>>>>> spin_lock_bh(&queue->state_lock);
>>>>>> if (queue->state != NVMET_TCP_Q_DISCONNECTING) {
>>>>>> queue->state = NVMET_TCP_Q_DISCONNECTING;
>>>>>> - queue_work(nvmet_wq, &queue->release_work);
>>>>>> + kref_put(&queue->kref, nvmet_tcp_release_queue);
>>>>>> }
>>>>>> spin_unlock_bh(&queue->state_lock);
>>>>>> }
>>>>>> @@ -1485,6 +1514,8 @@ static void
>>>>>> nvmet_tcp_release_queue_work(struct work_struct *w)
>>>>>> mutex_unlock(&nvmet_tcp_queue_mutex);
>>>>>> nvmet_tcp_restore_socket_callbacks(queue);
>>>>>> + tls_handshake_cancel(queue->sock->sk);
>>>>>> + cancel_delayed_work_sync(&queue->tls_handshake_work);
>>>>>
>>>>> We should call it tls_handshake_tmo_work or something to make it
>>>>> clear it is a timeout work.
>>>>>
>>>> Okay.
>>>>
>>>>>> cancel_work_sync(&queue->io_work);
>>>>>> /* stop accepting incoming data */
>>>>>> queue->rcv_state = NVMET_TCP_RECV_ERR;
>>>>>> @@ -1512,8 +1543,13 @@ 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 (likely(queue)) {
>>>>>> + if (queue->data_ready)
>>>>>> + queue->data_ready(sk);
>>>>>> + if (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 +1657,83 @@ 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_handshake_done(void *data, int status,
>>>>>> + key_serial_t peerid)
>>>>>> +{
>>>>>> + struct nvmet_tcp_queue *queue = data;
>>>>>> +
>>>>>> + pr_debug("queue %d: TLS handshake done, key %x, status %d\n",
>>>>>> + queue->idx, peerid, status);
>>>>>> + spin_lock_bh(&queue->state_lock);
>>>>>> + if (queue->state != NVMET_TCP_Q_TLS_HANDSHAKE) {
>>>>>
>>>>> Is this even possible?
>>>>>
>>>> I guess it can happen when the socket closes during handshake; the
>>>> daemon might still be sending a 'done' event but
>>>> nvmet_tcp_schedule_release_queue() has been called.
>>>
>>> Umm, if the socket closes during the handshake then the state
>>> is NVMET_TCP_Q_TLS_HANDSHAKE.
>>>
>> But there's a race window between setting it to
>> NVMET_TCP_Q_DISCONNECTING and calling tls_handshake_cancel().
>>
>>> p.s. you call handshake cancel in the release flow so you should be
>>> fenced properly no?
>> Not really. But I'll check if I can fix it up.
>
> The teardown handling feels complicated to me.
>
You tell me. TLS timeout handling always gets in the way.
But I've reworked it now to look slightly better.
> How are you testing it btw?
As outlined in the patchset description.
I've a target configuration running over the loopback interface.
Will expand to have two VMs talking to each other; however, that
needs more fiddling with the PSK deployment.
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@...e.de +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Ivo Totev, Andrew
Myers, Andrew McDonald, Martje Boudien Moerman
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