[PATCH v5 0/6] nvme-tcp: Support receiving KeyUpdate requests

alistair23
2025-11-12T04:28:15Z

From: Alistair Francis <alistair.francis@wdc.com>

The TLS 1.3 specification allows the TLS client or server to send a
KeyUpdate. This is generally used when the sequence is about to
overflow or after a certain amount of bytes have been encrypted.

The TLS spec doesn't mandate the conditions though, so a KeyUpdate
can be sent by the TLS client or server at any time. This includes
when running NVMe-OF over a TLS 1.3 connection.

As such Linux should be able to handle a KeyUpdate event, as the
other NVMe side could initiate a KeyUpdate.

Upcoming WD NVMe-TCP hardware controllers implement TLS support
and send KeyUpdate requests.

This series builds on top of the existing TLS EKEYEXPIRED work,
which already detects a KeyUpdate request. We can now pass that
information up to the NVMe layer (target and host) and then pass
it up to userspace.

Userspace (ktls-utils) will need to save the connection state
in the keyring during the initial handshake. The kernel then
provides the key serial back to userspace when handling a
KeyUpdate. Userspace can use this to restore the connection
information and then update the keys, this final process
is similar to the initial handshake.

This series depends on the recvmsg() kernel patch:
https://lore.kernel.org/linux-nvme/2cbe1350-0bf5-4487-be33-1d317cb73acf@suse.de/T/#mf56283228ae6c93e37dfbf1c0f6263910217cd80

ktls-utils (tlshd) userspace patches are available at:
https://lore.kernel.org/kernel-tls-handshake/CAKmqyKNpFhPtM8HAkgRMKQA8_N7AgoeqaSTe2=0spPnb+Oz2ng@mail.gmail.com/T/#mb277f5c998282666d0f41cc02f4abf516fcc4e9c

Link: https://datatracker.ietf.org/doc/html/rfc8446#section-4.6.3

Based-on: 2cbe1350-0bf5-4487-be33-1d317cb73acf@suse.de

v5:
- Cleanup code flow for nvme-tcp
- When using recvmsg in the host code first check for MSG_CTRUNC
in the msg_flags returned from recvmsg() and use that to determine
if it's a control message
- Drop clientkeyupdaterequest and serverkeyupdaterequest
v4:
- Don't stop the keep-alive timer
- Remove any support for sending a KeyUpdate
- Add tls_client_keyupdate_psk()' and 'tls_server_keyupdate_psk()'
- Code cleanups
- Change order of patches
v3:
- Rebase on the recvmsg() workflow patch
- Add debugfs support for the host
- Don't cancel an ongoing request
- Ensure a request is destructed on completion
v2:
- Change "key-serial" to "session-id"
- Fix reported build failures
- Drop tls_clear_err() function
- Stop keep alive timer during KeyUpdate
- Drop handshake message decoding in the NVMe layer

Alistair Francis (6):
net/handshake: Store the key serial number on completion
net/handshake: Define handshake_sk_destruct_req
net/handshake: Ensure the request is destructed on completion
net/handshake: Support KeyUpdate message types
nvme-tcp: Support KeyUpdate
nvmet-tcp: Support KeyUpdate

Documentation/netlink/specs/handshake.yaml | 20 +-
Documentation/networking/tls-handshake.rst | 1 +
drivers/nvme/host/tcp.c | 103 ++++++++--
drivers/nvme/target/tcp.c | 216 ++++++++++++++-------
include/net/handshake.h | 10 +-
include/uapi/linux/handshake.h | 12 ++
net/handshake/genl.c | 5 +-
net/handshake/request.c | 18 ++
net/handshake/tlshd.c | 96 ++++++++-
net/sunrpc/svcsock.c | 4 +-
net/sunrpc/xprtsock.c | 4 +-
11 files changed, 397 insertions(+), 92 deletions(-)

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2.51.1