Reorganize the Curve25519 library code:
- Build a single libcurve25519 module, instead of up to three modules:
libcurve25519, libcurve25519-generic, and an arch-specific module.
- Move the arch-specific Curve25519 code from arch/$(SRCARCH)/crypto/ to
lib/crypto/$(SRCARCH)/. Centralize the build rules into
lib/crypto/Makefile and lib/crypto/Kconfig.
- Include the arch-specific code directly in lib/crypto/curve25519.c via
a header, rather than using a separate .c file.
- Eliminate the entanglement with CRYPTO. CRYPTO_LIB_CURVE25519 no
longer selects CRYPTO, and the arch-specific Curve25519 code no longer
depends on CRYPTO.
This brings Curve25519 in line with the latest conventions for
lib/crypto/, used by other algorithms. The exception is that I kept the
generic code in separate translation units for now. (Some of the
function names collide between the x86 and generic Curve25519 code. And
the Curve25519 functions are very long anyway, so inlining doesn't
matter as much for Curve25519 as it does for some other algorithms.)
Link: https://lore.kernel.org/r/20250906213523.84915-11-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Move the Curve25519 test from an ad-hoc self-test to a KUnit test.
Generally keep the same test logic for now, just translated to KUnit.
There's one exception, which is that I dropped the incomplete test of
curve25519_generic(). The approach I'm taking to cover the different
implementations with the KUnit tests is to just rely on booting kernels
in QEMU with different '-cpu' options, rather than try to make the tests
(incompletely) test multiple implementations on one CPU. This way, both
the test and the library API are simpler.
This commit makes the file lib/crypto/curve25519.c no longer needed, as
its only purpose was to call the self-test. However, keep it for now,
since a later commit will add code to it again.
Temporarily omit the default value of CRYPTO_SELFTESTS that the other
lib/crypto/ KUnit tests have. It would cause a recursive kconfig
dependency, since the Curve25519 code is still entangled with CRYPTO. A
later commit will fix that.
Link: https://lore.kernel.org/r/20250906213523.84915-8-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
This patch moves the curve25519_selftest into curve25519.h so
we don't get a warning from gcc complaining about a missing
prototype.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Since we're doing a static inline dispatch here, we normally branch
based on whether or not there's an arch implementation. That would have
been fine in general, except the crypto Makefile prior used to turn
things off -- despite the Kconfig -- resulting in us needing to also
hard code various assembler things into the dispatcher too. The horror!
Now that the assembler config options are done by Kconfig, we can get
rid of the inconsistency.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Some older version of GAS do not support the ADX instructions, similarly
to how they also don't support AVX and such. This commit adds the same
build-time detection mechanisms we use for AVX and others for ADX, and
then makes sure that the curve25519 library dispatcher calls the right
functions.
Reported-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This contains two formally verified C implementations of the Curve25519
scalar multiplication function, one for 32-bit systems, and one for
64-bit systems whose compiler supports efficient 128-bit integer types.
Not only are these implementations formally verified, but they are also
the fastest available C implementations. They have been modified to be
friendly to kernel space and to be generally less horrendous looking,
but still an effort has been made to retain their formally verified
characteristic, and so the C might look slightly unidiomatic.
The 64-bit version comes from HACL*: https://github.com/project-everest/hacl-star
The 32-bit version comes from Fiat: https://github.com/mit-plv/fiat-crypto
Information: https://cr.yp.to/ecdh.html
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
[ardb: - move from lib/zinc to lib/crypto
- replace .c #includes with Kconfig based object selection
- drop simd handling and simplify support for per-arch versions ]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Eric Biggers