[PATCH net 00/24] net/rxrpc, crypto: Add Kerberos crypto lib and AF_RXRPC GSSAPI security class

David Howells
2025-02-03T14:23:59Z

Here's a set of patches to add basic support for the AF_RXRPC GSSAPI
security class. It provides transport security for keys that match the
security index 4 (OpenAFS) and security index 6 (YFS) for connections to
the AFS fileserver and VL server.

It can also be used to provide transport security on the callback channel,
but a further set of patches is required to provide the token and key to
set that up when the client responds to the fileserver's challenge.

[!] Note that these patches are on top of two fixes previously posted:

https://lore.kernel.org/netdev/20250203110307.7265-1-dhowells@redhat.com/

This series of patches consist of four parts:

(1) Provide an AEAD crypto driver, krb5enc, that mirrors the authenc
driver, but that hashes the plaintext, not the ciphertext. This was
made a separate module rather than just being a part of the authenc
driver because it has to do all of the constituent operations in the
opposite order - which impacts the async op handling.

Testmgr data is provided for AES+SHA2 and Camellia combinations of
authenc and krb5enc used by the krb5 library. AES+SHA1 is not
provided as the RFCs don't contain usable test vectors.

(2) Provide a Kerberos 5 crypto library. This is an extract from the
sunrpc driver as that code can be shared between sunrpc/nfs and
rxrpc/afs. This provides encryption, decryption, get MIC and verify
MIC routines that use and wrap the crypto functions, along with some
functions to provide layout management.

This supports AES+SHA1, AES+SHA2 and Camellia encryption types.

Self-testing is provided that goes further than is possible with
testmgr, doing subkey derivation as well.

(3) Push reponding to CHALLENGE packets over to recvmsg() or the kernel
equivalent so that the application layer can include user-defined
information in the RESPONSE packet. In a follow-up patch set, this
will allow the callback channel to be secured by the AFS filesystem.

(4) The AF_RXRPC RxGK security class that uses a key obtained from the AFS
GSS security service to do Kerberos 5-based encryption instead of
pcbc(fcrypt) and pcbc(des).

Can these all go through the same tree rather than the crypto bits going
via the crypto tree and the rxrpc bits needing to go via the networking
tree?

The patches can be found here also:

http://git.kernel.org/cgit/linux/kernel/git/dhowells/linux-fs.git/log/?h=crypto-krb5

David

David Howells (24):
crypto/krb5: Add API Documentation
crypto/krb5: Add some constants out of sunrpc headers
crypto: Add 'krb5enc' hash and cipher AEAD algorithm
crypto/krb5: Test manager data
crypto/krb5: Implement Kerberos crypto core
crypto/krb5: Add an API to query the layout of the crypto section
crypto/krb5: Add an API to alloc and prepare a crypto object
crypto/krb5: Add an API to perform requests
crypto/krb5: Provide infrastructure and key derivation
crypto/krb5: Implement the Kerberos5 rfc3961 key derivation
crypto/krb5: Provide RFC3961 setkey packaging functions
crypto/krb5: Implement the Kerberos5 rfc3961 encrypt and decrypt
functions
crypto/krb5: Implement the Kerberos5 rfc3961 get_mic and verify_mic
crypto/krb5: Implement the AES enctypes from rfc3962
crypto/krb5: Implement the AES enctypes from rfc8009
crypto/krb5: Implement the Camellia enctypes from rfc6803
crypto/krb5: Implement crypto self-testing
rxrpc: Pull out certain app callback funcs into an ops table
rxrpc: Pass CHALLENGE packets to the call for recvmsg() to respond to
rxrpc: Add the security index for yfs-rxgk
rxrpc: Add YFS RxGK (GSSAPI) security class
rxrpc: rxgk: Provide infrastructure and key derivation
rxrpc: rxgk: Implement the yfs-rxgk security class (GSSAPI)
rxrpc: rxgk: Implement connection rekeying

Documentation/crypto/index.rst | 1 +
Documentation/crypto/krb5.rst | 262 ++++++
crypto/Kconfig | 13 +
crypto/Makefile | 3 +
crypto/krb5/Kconfig | 26 +
crypto/krb5/Makefile | 18 +
crypto/krb5/internal.h | 247 ++++++
crypto/krb5/krb5_api.c | 452 ++++++++++
crypto/krb5/krb5_kdf.c | 145 ++++
crypto/krb5/rfc3961_simplified.c | 797 +++++++++++++++++
crypto/krb5/rfc3962_aes.c | 115 +++
crypto/krb5/rfc6803_camellia.c | 237 ++++++
crypto/krb5/rfc8009_aes2.c | 362 ++++++++
crypto/krb5/selftest.c | 544 ++++++++++++
crypto/krb5/selftest_data.c | 291 +++++++
crypto/krb5enc.c | 504 +++++++++++
crypto/testmgr.c | 16 +
crypto/testmgr.h | 351 ++++++++
fs/afs/Makefile | 1 +
fs/afs/cm_security.c | 54 ++
fs/afs/internal.h | 6 +
fs/afs/misc.c | 13 +
fs/afs/rxrpc.c | 16 +-
include/crypto/authenc.h | 2 +
include/crypto/krb5.h | 160 ++++
include/keys/rxrpc-type.h | 17 +
include/net/af_rxrpc.h | 37 +-
include/trace/events/rxrpc.h | 53 +-
include/uapi/linux/rxrpc.h | 63 +-
net/rxrpc/Kconfig | 10 +
net/rxrpc/Makefile | 5 +-
net/rxrpc/af_rxrpc.c | 45 +-
net/rxrpc/ar-internal.h | 57 +-
net/rxrpc/call_accept.c | 31 +-
net/rxrpc/call_object.c | 5 +-
net/rxrpc/conn_event.c | 97 ++-
net/rxrpc/conn_object.c | 2 +
net/rxrpc/insecure.c | 13 +-
net/rxrpc/io_thread.c | 8 +-
net/rxrpc/key.c | 185 ++++
net/rxrpc/output.c | 58 +-
net/rxrpc/protocol.h | 20 +
net/rxrpc/recvmsg.c | 114 ++-
net/rxrpc/rxgk.c | 1360 ++++++++++++++++++++++++++++++
net/rxrpc/rxgk_app.c | 285 +++++++
net/rxrpc/rxgk_common.h | 138 +++
net/rxrpc/rxgk_kdf.c | 287 +++++++
net/rxrpc/rxkad.c | 287 ++++---
net/rxrpc/rxperf.c | 10 +-
net/rxrpc/security.c | 3 +
net/rxrpc/sendmsg.c | 69 +-
net/rxrpc/server_key.c | 40 +
52 files changed, 7737 insertions(+), 198 deletions(-)
create mode 100644 Documentation/crypto/krb5.rst
create mode 100644 crypto/krb5/Kconfig
create mode 100644 crypto/krb5/Makefile
create mode 100644 crypto/krb5/internal.h
create mode 100644 crypto/krb5/krb5_api.c
create mode 100644 crypto/krb5/krb5_kdf.c
create mode 100644 crypto/krb5/rfc3961_simplified.c
create mode 100644 crypto/krb5/rfc3962_aes.c
create mode 100644 crypto/krb5/rfc6803_camellia.c
create mode 100644 crypto/krb5/rfc8009_aes2.c
create mode 100644 crypto/krb5/selftest.c
create mode 100644 crypto/krb5/selftest_data.c
create mode 100644 crypto/krb5enc.c
create mode 100644 fs/afs/cm_security.c
create mode 100644 include/crypto/krb5.h
create mode 100644 net/rxrpc/rxgk.c
create mode 100644 net/rxrpc/rxgk_app.c
create mode 100644 net/rxrpc/rxgk_common.h
create mode 100644 net/rxrpc/rxgk_kdf.c