[PATCH v6 0/2] Another crack at a handshake upcall mechanism

Chuck Lever
2023-03-03T18:51:26Z

Hi-

Here is v6 of a series to add generic support for transport layer
security handshake on behalf of kernel socket consumers (user space
consumers use a security library directly, of course). A summary of
the purpose of these patches is archived here:

https://lore.kernel.org/netdev/1DE06BB1-6BA9-4DB4-B2AA-07DE532963D6@oracle.com/

For v6, I've simplified the kernel TLS consumer API and added a few
new attributes to the handshake netlink protocol. Also featured is
the use of keyrings to restrict access to keying material. The
consumer TLS API documentation has been updated to reflect these
changes. This version also contains numerous bugfixes.

The full patch set to support SunRPC with TLSv1.3 is available in
the topic-rpc-with-tls-upcall branch here, based on net-next/main:

https://git.kernel.org/pub/scm/linux/kernel/git/cel/linux.git

A user space handshake agent for TLSv1.3 to go along with the kernel
patches is available in the "netlink" branch here:

https://github.com/oracle/ktls-utils

---

Changes since v5:
- Added a "timeout" attribute to the handshake netlink protocol
- Removed the GnuTLS-specific "priorities" attribute
- Added support for keyrings to restrict access to keys
- Simplified the kernel consumer TLS handshake API
- The handshake netlink protocol can handle multiple peer IDs or
certificates in the ACCEPT and DONE operations, though the
implementation does not yet support it.

Changes since v4:
- Rebased onto net-next/main
- Replaced req reference counting with ->sk_destruct
- CMD_ACCEPT now does the equivalent of a dup(2) rather than an
accept(2)
- CMD_DONE no longer closes the user space socket endpoint
- handshake_req_cancel is now tested and working
- Added a YAML specification for the netlink upcall protocol, and
simplified the protocol to fit the YAML schema
- Added an initial set of tracepoints

Changes since v3:
- Converted all netlink code to use Generic Netlink
- Reworked handshake request lifetime logic throughout
- Global pending list is now per-net
- On completion, return the remote's identity to the consumer

Changes since v2:
- PF_HANDSHAKE replaced with NETLINK_HANDSHAKE
- Replaced listen(2) / poll(2) with a multicast notification service
- Replaced accept(2) with a netlink operation that can return an
open fd and handshake parameters
- Replaced close(2) with a netlink operation that can take arguments

Changes since RFC:
- Generic upcall support split away from kTLS
- Added support for TLS ServerHello
- Documentation has been temporarily removed while API churns

---

Chuck Lever (2):
net/handshake: Create a NETLINK service for handling handshake requests
net/tls: Add kernel APIs for requesting a TLSv1.3 handshake

Documentation/netlink/specs/handshake.yaml | 139 ++++++++
Documentation/networking/index.rst | 1 +
Documentation/networking/tls-handshake.rst | 219 ++++++++++++
include/net/handshake.h | 46 +++
include/net/net_namespace.h | 5 +
include/net/sock.h | 1 +
include/net/tls.h | 29 ++
include/trace/events/handshake.h | 159 +++++++++
include/uapi/linux/handshake.h | 73 ++++
net/Makefile | 1 +
net/handshake/Makefile | 11 +
net/handshake/handshake.h | 41 +++
net/handshake/netlink.c | 346 ++++++++++++++++++
net/handshake/request.c | 246 +++++++++++++
net/handshake/trace.c | 17 +
net/tls/Makefile | 2 +-
net/tls/tls_handshake.c | 391 +++++++++++++++++++++
17 files changed, 1726 insertions(+), 1 deletion(-)
create mode 100644 Documentation/netlink/specs/handshake.yaml
create mode 100644 Documentation/networking/tls-handshake.rst
create mode 100644 include/net/handshake.h
create mode 100644 include/trace/events/handshake.h
create mode 100644 include/uapi/linux/handshake.h
create mode 100644 net/handshake/Makefile
create mode 100644 net/handshake/handshake.h
create mode 100644 net/handshake/netlink.c
create mode 100644 net/handshake/request.c
create mode 100644 net/handshake/trace.c
create mode 100644 net/tls/tls_handshake.c

--
Chuck Lever