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    Subject[PATCH v4 00/21] net/tcp: Add TCP-AO support
    Date
    In TODO (expect in next versions):
    - Documentation/ page about TCP-AO kernel design, UAPI
    - setsockopt(TCP_REPAIR) with TCP-AO
    - getsockopt() to return TCP-AO counters (per-MKT & per-ao_info)
    - tcp_{v4,v6}_send_reset() to support TCP-AO RST signing on request sockets
    - TCP-AO and TCP-MD5 interraction in non/default VRFs: more selftests
    - check getsockopt() with VRFs (currently untested)

    This is also available as a git branch for pulling:
    https://github.com/0x7f454c46/linux/tree/tcp-ao-v4
    And another branch with selftests, that will be sent later separately:
    https://github.com/0x7f454c46/linux/tree/tcp-ao-v4-with-selftests

    Changes from v3:
    - TCP_MD5 dynamic static key enable/disable patches merged separately [4]
    - crypto_pool patches were nacked [5], so instead this patch set extends
    TCP-MD5-sigpool to be used for TCP-AO as well as for TCP-MD5
    - Added missing `static' for tcp_v6_ao_calc_key()
    (kernel test robot <lkp@intel.com>)
    - Removed CONFIG_TCP_AO default=y and added "If unsure, say N."
    - Don't leak ao_info and don't create an unsigned TCP socket if there was
    a TCP-AO key during handshake, but it was removed from listening socket
    while the connection was being established
    - Migrate to use static_key_fast_inc_not_disabled() and check return
    code of static_branch_inc()
    - Change some return codes to EAFNOSUPPORT for error-pathes where
    family is neither AF_INET nor AF_INET6
    - setsockopt()s on a closed/listen socket might have created stray ao_info,
    remove it if connect() is called with a correct TCP-MD5 key, the same
    for the reverse situation: remove md5sig_info straight away from the
    socket if it's going to be TCP-AO connection
    - IPv4-mapped-IPv6 addresses + selftest in fcnal-test.sh (by Salam)
    - fix using uninitialized sisn/disn from stack - it would only make
    non-SYN packets fail verification on a listen socket, which are not
    expected anyway (kernel test robot <lkp@intel.com>)
    - implicit padding in UAPI TCP-AO structures converted to explicit
    (spotted-by David Laight)
    - Some selftests missed zero-initializers for uapi structs on stack
    - Removed tcp_ao_do_lookup_rcvid() and tcp_ao_do_lookup_sndid() in
    favor of unified tcp_ao_matched_key()
    - Disallowed setting current/rnext keys on listen sockets - that wasn't
    supported and didn't affect anything, cleanup for the UAPI
    - VRFs support for TCP-AO

    Changes from v2:
    - Added more missing `static' declarations for local functions
    (kernel test robot <lkp@intel.com>)
    - Building now with CONFIG_TCP_AO=n and CONFIG_TCP_MD5SIG=n
    (kernel test robot <lkp@intel.com>)
    - Now setsockopt(TCP_AO) is allowed when it's TCP_LISTEN or TCP_CLOSE
    state OR the key added is not the first key on a socket (by Salam)
    - CONFIG_TCP_AO does not depend on CONFIG_TCP_MD5SIG anymore
    - Don't leak tcp_md5_needed static branch counter when TCP-MD5 key
    is modified/changed
    - TCP-AO lookups are dynamically enabled/disabled with static key when
    there is ao_info in the system (and when it is destroyed)
    - Wired SYN cookies up to TCP-AO (by Salam)
    - Fix verification for possible re-transmitted SYN packets (by Salam)
    - use sockopt_lock_sock() instead of lock_sock()
    (from v6.1 rebase, commit d51bbff2aba7)
    - use sockptr_t in getsockopt(TCP_AO_GET)
    (from v6.1 rebase, commit 34704ef024ae)
    - Fixed reallocating crypto_pool's scratch area by IPI while
    crypto_pool_get() was get by another CPU
    - selftests on older kernels (or with CONFIG_TCP_AO=n) should exit with
    SKIP, not FAIL (Shuah Khan <shuah@kernel.org>)
    - selftests that check interaction between TCP-AO and TCP-MD5 now
    SKIP when CONFIG_TCP_MD5SIG=n
    - Measured the performance of different hashing algorithms for TCP-AO
    and compare with TCP-MD5 performance. This is done with hacky patches
    to iperf (see [3]). At this moment I've done it in qemu/KVM with CPU
    affinities set on Intel(R) Core(TM) i7-7600U CPU @ 2.80GHz.
    No performance degradation was noticed before/after patches, but given
    the measures were done in a VM, without measuring it on a physical dut
    it only gives a hint of relative speed for different hash algorithms
    with TCP-AO. Here are results, averaging on 30 measures each:
    TCP: 3.51Gbits/sec
    TCP-MD5: 1.12Gbits/sec
    TCP-AO(HMAC(SHA1)): 1.53Gbits/sec
    TCP-AO(CMAC(AES128)): 621Mbits/sec
    TCP-AO(HMAC(SHA512)): 1.21Gbits/sec
    TCP-AO(HMAC(SHA384)): 1.20Gbits/sec
    TCP-AO(HMAC(SHA224)): 961Mbits/sec
    TCP-AO(HMAC(SHA3-512)): 157Mbits/sec
    TCP-AO(HMAC(RMD160)): 659Mbits/sec
    TCP-AO(HMAC(MD5): 1.12Gbits/sec
    (the last one is just for fun, but may make sense as it provides
    the same security as TCP-MD5, but allows multiple keys and a mechanism
    to change them from RFC5925)

    Changes from v1:
    - Building now with CONFIG_IPV6=n (kernel test robot <lkp@intel.com>)
    - Added missing static declarations for local functions
    (kernel test robot <lkp@intel.com>)
    - Addressed static analyzer and review comments by Dan Carpenter
    (thanks, they were very useful!)
    - Fix elif without defined() for !CONFIG_TCP_AO
    - Recursively build selftests/net/tcp_ao (Shuah Khan), patches in:
    https://lore.kernel.org/all/20220919201958.279545-1-dima@arista.com/T/#u
    - Don't leak crypto_pool reference when TCP-MD5 key is modified/changed
    - Add TCP-AO support for nettest.c and fcnal-test.sh
    (will be used for VRF testing in later versions)

    Comparison between Leonard proposal and this (overview):
    https://lore.kernel.org/all/3cf03d51-74db-675c-b392-e4647fa5b5a6@arista.com/T/#u

    Version 2: https://lore.kernel.org/all/20220923201319.493208-1-dima@arista.com/T/#u
    Version 1: https://lore.kernel.org/all/20220818170005.747015-1-dima@arista.com/T/#u

    This patchset implements the TCP-AO option as described in RFC5925. There
    is a request from industry to move away from TCP-MD5SIG and it seems the time
    is right to have a TCP-AO upstreamed. This TCP option is meant to replace
    the TCP MD5 option and address its shortcomings. Specifically, it provides
    more secure hashing, key rotation and support for long-lived connections
    (see the summary of TCP-AO advantages over TCP-MD5 in (1.3) of RFC5925).
    The patch series starts with six patches that are not specific to TCP-AO
    but implement a general crypto facility that we thought is useful
    to eliminate code duplication between TCP-MD5SIG and TCP-AO as well as other
    crypto users. These six patches are being submitted separately in
    a different patchset [1]. Including them here will show better the gain
    in code sharing. Next are 18 patches that implement the actual TCP-AO option,
    followed by patches implementing selftests.

    The patch set was written as a collaboration of three authors (in alphabetical
    order): Dmitry Safonov, Francesco Ruggeri and Salam Noureddine. Additional
    credits should be given to Prasad Koya, who was involved in early prototyping
    a few years back. There is also a separate submission done by Leonard Crestez
    whom we thank for his efforts getting an implementation of RFC5925 submitted
    for review upstream [2]. This is an independent implementation that makes
    different design decisions.

    For example, we chose a similar design to the TCP-MD5SIG implementation and
    used setsockopts to program per-socket keys, avoiding the extra complexity
    of managing a centralized key database in the kernel. A centralized database
    in the kernel has dubious benefits since it doesn’t eliminate per-socket
    setsockopts needed to specify which sockets need TCP-AO and what are the
    currently preferred keys. It also complicates traffic key caching and
    preventing deletion of in-use keys.

    In this implementation, a centralized database of keys can be thought of
    as living in user space and user applications would have to program those
    keys on matching sockets. On the server side, the user application programs
    keys (MKTS in TCP-AO nomenclature) on the listening socket for all peers that
    are expected to connect. Prefix matching on the peer address is supported.
    When a peer issues a successful connect, all the MKTs matching the IP address
    of the peer are copied to the newly created socket. On the active side,
    when a connect() is issued all MKTs that do not match the peer are deleted
    from the socket since they will never match the peer. This implementation
    uses three setsockopt()s for adding, deleting and modifying keys on a socket.
    All three setsockopt()s have extensive sanity checks that prevent
    inconsistencies in the keys on a given socket. A getsockopt() is provided
    to get key information from any given socket.

    Few things to note about this implementation:
    - Traffic keys are cached for established connections avoiding the cost of
    such calculation for each packet received or sent.
    - Great care has been taken to avoid deleting in-use MKTs
    as required by the RFC.
    - Any crypto algorithm supported by the Linux kernel can be used
    to calculate packet hashes.
    - Fastopen works with TCP-AO but hasn’t been tested extensively.
    - Tested for interop with other major networking vendors (on linux-4.19),
    including testing for key rotation and long lived connections.

    [1]: https://lore.kernel.org/all/20220726201600.1715505-1-dima@arista.com/
    [2]: https://lore.kernel.org/all/cover.1658815925.git.cdleonard@gmail.com/
    [3]: https://github.com/0x7f454c46/iperf/tree/tcp-md5-ao
    [4]: https://lore.kernel.org/all/166995421700.16716.17446147162780881407.git-patchwork-notify@kernel.org/T/#u
    [5]: https://lore.kernel.org/all/Y8kSkW4X4vQdFyOl@gondor.apana.org.au/T/#u

    Cc: Andy Lutomirski <luto@amacapital.net>
    Cc: Ard Biesheuvel <ardb@kernel.org>
    Cc: Bob Gilligan <gilligan@arista.com>
    Cc: Dan Carpenter <dan.carpenter@oracle.com>
    Cc: David Ahern <dsahern@kernel.org>
    Cc: David Laight <David.Laight@aculab.com>
    Cc: "David S. Miller" <davem@davemloft.net>
    Cc: Dmitry Safonov <0x7f454c46@gmail.com>
    Cc: Eric Biggers <ebiggers@kernel.org>
    Cc: Eric Dumazet <edumazet@google.com>
    Cc: "Eric W. Biederman" <ebiederm@xmission.com>
    Cc: Francesco Ruggeri <fruggeri05@gmail.com>
    Cc: Herbert Xu <herbert@gondor.apana.org.au>
    Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
    Cc: Ivan Delalande <colona@arista.com>
    Cc: Jakub Kicinski <kuba@kernel.org>
    Cc: Leonard Crestez <cdleonard@gmail.com>
    Cc: Paolo Abeni <pabeni@redhat.com>
    Cc: Salam Noureddine <noureddine@arista.com>
    Cc: netdev@vger.kernel.org
    Cc: linux-kernel@vger.kernel.org

    Dmitry Safonov (21):
    net/tcp: Prepare tcp_md5sig_pool for TCP-AO
    tcp: Add TCP-AO config and structures
    net/tcp: Introduce TCP_AO setsockopt()s
    net/tcp: Prevent TCP-MD5 with TCP-AO being set
    net/tcp: Calculate TCP-AO traffic keys
    net/tcp: Add TCP-AO sign to outgoing packets
    net/tcp: Add tcp_parse_auth_options()
    net/tcp: Add AO sign to RST packets
    net/tcp: Add TCP-AO sign to twsk
    net/tcp: Wire TCP-AO to request sockets
    net/tcp: Sign SYN-ACK segments with TCP-AO
    net/tcp: Verify inbound TCP-AO signed segments
    net/tcp: Add TCP-AO segments counters
    net/tcp: Add TCP-AO SNE support
    net/tcp: Add tcp_hash_fail() ratelimited logs
    net/tcp: Ignore specific ICMPs for TCP-AO connections
    net/tcp: Add option for TCP-AO to (not) hash header
    net/tcp: Add getsockopt(TCP_AO_GET)
    net/tcp: Allow asynchronous delete for TCP-AO keys (MKTs)
    net/tcp-ao: Add static_key for TCP-AO
    net/tcp-ao: Wire up l3index to TCP-AO

    include/linux/sockptr.h | 23 +
    include/linux/tcp.h | 30 +-
    include/net/dropreason.h | 25 +
    include/net/tcp.h | 207 +++-
    include/net/tcp_ao.h | 306 ++++++
    include/uapi/linux/snmp.h | 5 +
    include/uapi/linux/tcp.h | 73 ++
    net/ipv4/Kconfig | 17 +
    net/ipv4/Makefile | 2 +
    net/ipv4/proc.c | 5 +
    net/ipv4/syncookies.c | 4 +
    net/ipv4/tcp.c | 192 ++--
    net/ipv4/tcp_ao.c | 2130 +++++++++++++++++++++++++++++++++++++
    net/ipv4/tcp_input.c | 105 +-
    net/ipv4/tcp_ipv4.c | 354 ++++--
    net/ipv4/tcp_minisocks.c | 35 +-
    net/ipv4/tcp_output.c | 211 +++-
    net/ipv4/tcp_sigpool.c | 333 ++++++
    net/ipv6/Makefile | 1 +
    net/ipv6/syncookies.c | 5 +
    net/ipv6/tcp_ao.c | 149 +++
    net/ipv6/tcp_ipv6.c | 372 +++++--
    22 files changed, 4251 insertions(+), 333 deletions(-)
    create mode 100644 include/net/tcp_ao.h
    create mode 100644 net/ipv4/tcp_ao.c
    create mode 100644 net/ipv4/tcp_sigpool.c
    create mode 100644 net/ipv6/tcp_ao.c


    base-commit: e1c04510f521e853019afeca2a5991a5ef8d6a5b
    --
    2.39.1

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