[RFC 0/4] net/tls: add support for the record size limit extension

[Wilfred Mallawa]

From: Wilfred Mallawa <wilfred.mallawa@xxxxxxx>

During a tls handshake, an endpoint may specify a maximum record size limit. As
specified by [1]. which allows peers to negotiate a maximum plaintext record
size during the TLS handshake. If a TLS endpoint receives a record larger
than its advertised limit, it must send a fatal "record_overflow" alert [1].
Currently, this limit is not visble to the kernel, particularly in the case
where userspace handles the handshake (tlshd/gnutls).

This series in conjunction with the respective userspace changes for tlshd [2]
and gnutls [3], adds support for the kernel the receive the negotiated record
size limit through the existing netlink communication layer, and use this
value to limit outgoing records to the size specified.

[1] https://www.rfc-editor.org/rfc/rfc8449
[2] https://github.com/oracle/ktls-utils/pull/112
[3] https://gitlab.com/gnutls/gnutls/-/merge_requests/1989

Wilfred Mallawa (4):
  net/handshake: get negotiated tls record size limit
  net/tls/tls_sw: use the record size limit specified
  nvme/host/tcp: set max record size in the tls context
  nvme/target/tcp: set max record size in the tls context

 Documentation/netlink/specs/handshake.yaml |  3 +++
 Documentation/networking/tls-handshake.rst |  8 +++++++-
 drivers/nvme/host/tcp.c                    | 18 +++++++++++++++++-
 drivers/nvme/target/tcp.c                  | 16 +++++++++++++++-
 include/net/handshake.h                    |  4 +++-
 include/net/tls.h                          |  1 +
 include/uapi/linux/handshake.h             |  1 +
 net/handshake/genl.c                       |  5 +++--
 net/handshake/tlshd.c                      | 15 +++++++++++++--
 net/sunrpc/svcsock.c                       |  4 +++-
 net/sunrpc/xprtsock.c                      |  4 +++-
 net/tls/tls_sw.c                           | 10 +++++++++-
 12 files changed, 78 insertions(+), 11 deletions(-)

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2.50.1