[PATCH v2 00/20] nvme: fixes, cleanups and enhancements to the dhchap-auth host code

Sagi Grimberg
2022-11-13T11:24:35Z

Currently the authentication code is fairly fragile with respect to
mutual locking between secrets sysfs override, re-authentication, and
controller resets.

This patch set attempts to resolve these issues by:
1. freeing queue chap context as soon as authentication completes
- including making the chap 4k buffer short-lived (added a mempool
to overcome memory pressure situations).
2. allocate a simple vector for queue chap contexts so there is
no list/tree traversal to resolve queue chap context. queue chap
contexts are 1x1 mapped to queues, which are stored in a vector as
well.
3. flush chap auth_work from the ctrl dhchap work, this simplifies
how we flush inflight authentication sequence
4. use ctrl dhchap_auth_mutex to protect only the resources that are
accessed and modified via sysfs and the authentication flow (i.e. ctrl
host_key and ctrl_key)
5. move drivers (rdma/tcp) nvme_auth_stop later in the error recovery
flow to expedite failover and not block on I/O.

Feedback is welcome.

Changes from v1:
- split some of list->array conversion patch to make it simpler to review
still it involves the locking changes in it so no regression is introduced.
- removed dhchap array macro foreach and accessor as the dhchap queue context
is now typed in nvme_ctrl.
- Added mempool for chap buffers to overcome memory pressure situations
- removed redundant chap->buf_size
- renamed __nvme_auth_work to nvme_queue_auth_work (also nvme_dhchap_auth_work
to nvme_ctrl_auth_work)
- converted macro to static inline function (ctrl_max_dhchaps)

Sagi Grimberg (20):
nvme-auth: rename __nvme_auth_[reset|free] to
nvme_auth[reset|free]_dhchap
nvme-auth: rename authentication work elements
nvme-auth: remove symbol export from nvme_auth_reset
nvme-auth: don't re-authenticate if the controller is not LIVE
nvme-auth: remove redundant buffer deallocations
nvme-auth: don't ignore key generation failures when initializing ctrl
keys
nvme-auth: don't override ctrl keys before validation
nvme-auth: remove redundant if statement
nvme-auth: don't keep long lived 4k dhchap buffer
nvme-auth: guarantee dhchap buffers under memory pressure
nvme-auth: clear sensitive info right after authentication completes
nvme-auth: remove redundant deallocations
nvme-auth: no need to reset chap contexts on re-authentication
nvme-auth: check chap ctrl_key once constructed
nvme: move nvme_dhchap_queue_context declaration to nvme.h header
nvme-auth: convert dhchap_auth_list to an array
nvme-auth: remove redundant auth_work flush
nvme-auth: have dhchap_auth_work wait for queues auth to complete
nvme-tcp: stop auth work after tearing down queues in error recovery
nvme-rdma: stop auth work after tearing down queues in error recovery

drivers/nvme/host/auth.c | 282 ++++++++++++++++++---------------------
drivers/nvme/host/core.c | 32 ++++-
drivers/nvme/host/nvme.h | 43 +++++-
drivers/nvme/host/rdma.c | 2 +-
drivers/nvme/host/tcp.c | 2 +-
5 files changed, 200 insertions(+), 161 deletions(-)

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2.34.1