nvme-auth: always set valid seq_num in dhchap reply

Currently a seqnum of zero is sent during uni-directional
authentication. The zero value is reserved for the secure channel
feature which is not yet implemented.

Relevant extract from the spec:
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

Signed-off-by: Mark O'Donovan <shiftee@posteo.net>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>

nvmet-auth: complete a request only after freeing the dhchap pointers

It may happen that the work to destroy a queue
(for example nvmet_tcp_release_queue_work()) is started while
an auth-send or auth-receive command is still completing.

nvmet_sq_destroy() will block, waiting for all the references
to the sq to be dropped, the last reference is then
dropped when nvmet_req_complete() is called.

When this happens, both nvmet_sq_destroy() and
nvmet_execute_auth_send()/_receive() will free the dhchap pointers by
calling nvmet_auth_sq_free().
Since there isn't any lock, the two threads may race against each other,
causing double frees and memory corruptions, as reported by KASAN.

Reproduced by stress blktests nvme/041 nvme/042 nvme/043

nvme nvme2: qid 0: authenticated with hash hmac(sha512) dhgroup ffdhe4096
==================================================================
BUG: KASAN: double-free in kfree+0xec/0x4b0

Call Trace:
<TASK>
kfree+0xec/0x4b0
nvmet_auth_sq_free+0xe1/0x160 [nvmet]
nvmet_execute_auth_send+0x482/0x16d0 [nvmet]
process_one_work+0x8e5/0x1510

Allocated by task 191846:
__kasan_kmalloc+0x81/0xa0
nvmet_auth_ctrl_sesskey+0xf6/0x380 [nvmet]
nvmet_auth_reply+0x119/0x990 [nvmet]

Freed by task 143270:
kfree+0xec/0x4b0
nvmet_auth_sq_free+0xe1/0x160 [nvmet]
process_one_work+0x8e5/0x1510

Fix this bug by calling nvmet_req_complete() only after freeing the
pointers, so we will prevent the race by holding the sq reference.

V2: remove redundant code

Fixes: db1312dd9548 ("nvmet: implement basic In-Band Authentication")
Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>

nvmet-auth: remove unnecessary break after goto

Remove dead break after goto.

Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>

nvmet-auth: remove some dead code

'status' is known to be 0 at the point.
And nvmet_auth_challenge() return a -E<ERROR_CODE> or 0.
So these lines of code should just be removed.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>

nvmet-auth: don't try to cancel a non-initialized work_struct

Currently blktests nvme/002 trips up debugobjects if CONFIG_NVME_AUTH is
enabled, but authentication is not on a queue. This is because
nvmet_auth_sq_free cancels sq->auth_expired_work unconditionaly, while
auth_expired_work is only ever initialized if authentication is enabled
for a given controller.

Fix this by calling most of what is nvmet_init_auth unconditionally
when initializing the SQ, and just do the setting of the result
field in the connect command handler.

Fixes: db1312dd9548 ("nvmet: implement basic In-Band Authentication")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Hannes Reinecke <hare@suse.de>

nvmet-auth: remove redundant parameters req

The parameter is not used in this function, so remove it.

Signed-off-by: Genjian Zhang <zhanggenjian@kylinos.cn>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvmet-auth: clean up with done_kfree

Jump directly to done_kfree to release d, which is consistent with the
code style behind.

Reported-by: Genjian Zhang <zhanggenjian@kylinos.cn>
Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvmet-auth: use kmemdup instead of kmalloc + memcpy

For code neat purpose, we can use kmemdup to replace
kmalloc + memcpy.

Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvmet-auth: fix return value check in auth receive

nvmet_auth_challenge() return type is int and currently it uses status
variable that is of type u16 in nvmet_execute_auth_receive().

Catch the return value of nvmet_auth_challenge() into int and set the
NVME_SC_INTERNAL as status variable before we jump to error.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvmet-auth: fix return value check in auth send

nvmet_setup_auth() return type is int and currently it uses status
variable that is of type u16 in nvmet_execute_auth_send().

Catch the return value of nvmet_setup_auth() into int and set the
NVME_SC_INTERNAL as status variable before we jump to error.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvmet-auth: expire authentication sessions

Each authentication step is required to be completed within the
KATO interval (or two minutes if not set). So add a workqueue function
to reset the transaction ID and the expected next protocol step;
this will automatically the next authentication command referring
to the terminated authentication.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvmet-auth: Diffie-Hellman key exchange support

Implement Diffie-Hellman key exchange using FFDHE groups for NVMe
In-Band Authentication.
This patch adds a new host configfs attribute 'dhchap_dhgroup' to
select the FFDHE group to use.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvmet: implement basic In-Band Authentication

Implement NVMe-oF In-Band authentication according to NVMe TPAR 8006.
This patch adds three additional configfs entries 'dhchap_key',
'dhchap_ctrl_key', and 'dhchap_hash' to the 'host' configfs directory.
The 'dhchap_key' and 'dhchap_ctrl_key' entries need to be in the ASCII
format as specified in NVMe Base Specification v2.0 section 8.13.5.8
'Secret representation'.
'dhchap_hash' defaults to 'hmac(sha256)', and can be written to to
switch to a different HMAC algorithm.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>