drm_connector_attach_encoder() is now called by
drm_bridge_connector_init().
Reviewed-by: Liu Ying <victor.liu@nxp.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://patch.msgid.link/20260423115550.444930-5-luca.ceresoli@bootlin.com
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Currently all users of the bridge-connector must call
drm_connector_attach_encoder() immediately after a successful
drm_bridge_connector_init().
This is an unnecessary burden for users. Move the call to the end of
drm_bridge_connector_init() so all callers can be simplified.
Update documentation accordingly, rewording a bit the whole paragraph which
would otherwise become poorly readable due to the growing list of actions.
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://patch.msgid.link/20260423-drm-bridge-connector-attach_encoder-v2-1-2ae6ca69b390@bootlin.com
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Convert probe error handling to use dev_err_probe() which provides
proper handling of -EPROBE_DEFER.
Signed-off-by: Sheetal <sheetal@nvidia.com>
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Eric Biggers says:
====================
Reimplement TCP-AO using crypto library
This series can also be retrieved from:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux.git tcp-ao-v2
This series is targeting net-next for 7.2. To make this series
self-contained in the networking code, I dropped the patches that remove
support for transformation cloning from the crypto API, which is a
further negative 275-line cleanup and optimization this series enables.
That will be done as a follow-up, either through the crypto tree for
7.3, or still through net-next for 7.2 at maintainer preference.
This series refactors the TCP-AO (TCP Authentication Option) code to do
MAC and KDF computations using lib/crypto/ instead of crypto_ahash.
This greatly simplifies the code and makes it much more efficient. The
entire tcp_sigpool mechanism becomes unnecessary and is removed, as the
problems it was designed to solve don't exist with the library APIs.
The crypto API's support for crypto transformation cloning also becomes
unnecessary and will be removed in follow-up patches. Note that as part
of that, we'll be able to roll back the addition of the reference count
to crypto_tfm, which had regressed performance for all crypto API users.
To make this simplification and optimization possible, this series also
updates the TCP-AO code to support a specific set of algorithms, rather
than arbitrary algorithms that don't make sense and are very likely not
being used, e.g. CRC-32 and HMAC-MD5.
Specifically, this series retains the support for AES-128-CMAC,
HMAC-SHA1, and HMAC-SHA256. AES-128-CMAC and HMAC-SHA1 are the only
algorithms that are actually standardized for use in TCP-AO, while
HMAC-SHA256 makes sense to continue supporting as a Linux extension. Of
course, other algorithms can still be (re-)added later if ever needed.
It's worth noting that TCP-AO MACs are limited to 20 bytes by the TCP
options space, which limits the benefit of further algorithm upgrades.
This series passes the tcp_ao selftests
(sudo make -C tools/testing/selftests/net/tcp_ao/ run_tests).
To get a sense for how much more efficient this makes the TCP-AO code,
here's a microbenchmark for tcp_ao_hash_skb() with skb->len == 128:
Algorithm Avg cycles (before) Avg cycles (after)
--------- ------------------- ------------------
HMAC-SHA1 3319 1256
HMAC-SHA256 3311 1344
AES-128-CMAC 2720 1107
====================
Link: https://patch.msgid.link/20260427172727.9310-1-ebiggers@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
tcp_sigpool is no longer used. It existed only as a workaround for
issues in the design of the crypto_ahash API, which have been avoided by
switching to the much easier-to-use library APIs instead. Remove it.
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Link: https://patch.msgid.link/20260427172727.9310-6-ebiggers@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Since tcp-ao now uses the crypto library API instead of crypto_ahash,
and MACs and keys now have a statically-known maximum size, many tcp-ao
functions can no longer fail. Propagate this change up into the return
types of various functions.
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Link: https://patch.msgid.link/20260427172727.9310-5-ebiggers@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Now that the maximum MAC and traffic key lengths are statically-known
small values, allocate MACs and traffic keys on the stack instead of
with kmalloc. This eliminates multiple failure-prone GFP_ATOMIC
allocations.
Note that some cases such as tcp_ao_prepare_reset() are left unchanged
for now since they would require slightly wider changes.
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Link: https://patch.msgid.link/20260427172727.9310-4-ebiggers@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Currently the kernel's TCP-AO implementation does the MAC and KDF
computations using the crypto_ahash API. This API is inefficient and
difficult to use, and it has required extensive workarounds in the form
of per-CPU preallocated objects (tcp_sigpool) to work at all.
Let's use lib/crypto/ instead. This means switching to straightforward
stack-allocated structures, virtually addressed buffers, and direct
function calls. It also means removing quite a bit of error handling.
This makes TCP-AO quite a bit faster.
This also enables many additional cleanups, which later commits will
handle: removing tcp-sigpool, removing support for crypto_tfm cloning,
removing more error handling, and replacing more dynamically-allocated
buffers with stack buffers based on the now-statically-known limits.
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Link: https://patch.msgid.link/20260427172727.9310-3-ebiggers@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
RFC 5926 (https://datatracker.ietf.org/doc/html/rfc5926) specifies the
use of AES-128-CMAC and HMAC-SHA1 with TCP-AO. This includes a
specification for how traffic keys shall be derived for each algorithm.
Support for any other algorithms with TCP-AO isn't standardized, though
an expired Internet Draft (a work-in-progress document, not a standard)
from 2019 does propose adding HMAC-SHA256 support:
https://datatracker.ietf.org/doc/html/draft-nayak-tcp-sha2-03
Since both documents specify the KDF for each algorithm individually, it
isn't necessarily clear how any other algorithm should be integrated.
Nevertheless, the Linux implementation of TCP-AO allows userspace to
specify the MAC algorithm as a string tcp_ao_add::alg_name naming either
"cmac(aes128)" or an arbitrary algorithm in the crypto_ahash API. The
set of valid strings is undocumented. The implementation assumes that
"cmac(aes128)" is the only algorithm that requires an entropy extraction
step and that all algorithms accept keys with length equal to the
untruncated MAC; thus, arbitrary HMAC algorithms probably do work, but
some other MAC algorithms like AES-256-CMAC have never actually worked.
Unfortunately, this undocumented string allows many obsolete, insecure,
or redundant algorithms. For example, "hmac(md5)" and the
non-cryptographic "crc32" are accepted. It also ties the implementation
to crypto_ahash and requires that most memory be dynamically allocated,
making the implementation unnecessarily complex and inefficient. Still
furthermore, this implementation requires the crypto API to support
"transformation cloning", whose only user is this feature.
Fortunately, it's very likely that only a few algorithms are actually
used in practice. Let's restrict the set of allowed algorithms to
"cmac(aes128)" (or "cmac(aes)" with keylen=16), "hmac(sha1)", and
"hmac(sha256)". The first two are the actually standard ones, while
HMAC-SHA256 seems like a reasonable algorithm to continue supporting as
a Linux extension, considering the Internet Draft for it and the fact
that SHA-256 is the usual choice of upgrade from the outdated SHA-1.
If any other algorithm ever turns out to be needed, e.g. HMAC-SHA512, it
can of course be (re-)added in library form. However, note that the TCP
options space limits TCP-AO MACs to 20 bytes (160 bits) anyway, which
limits the potential benefit of any further upgrade to the algorithm.
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Link: https://patch.msgid.link/20260427172727.9310-2-ebiggers@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
