commit 44e8241c51f762aafa50ed116da68fd6ecdcc954 upstream.

On big endian arm kernels, the arm optimized Curve25519 code produces incorrect outputs and fails the Curve25519 test. This has been true ever since this code was added.

It seems that hardly anyone (or even no one?) actually uses big endian arm kernels. But as long as they're ostensibly supported, we should disable this code on them so that it's not accidentally used.

Note: for future-proofing, use !CPU_BIG_ENDIAN instead of CPU_LITTLE_ENDIAN. Both of these are arch-specific options that could get removed in the future if big endian support gets dropped.

Fixes: d8f1308a025f ("crypto: arm/curve25519 - wire up NEON implementation") Cc: stable@vger.kernel.org Acked-by: Ard Biesheuvel ardb@kernel.org Link: https://lore.kernel.org/r/20251104054906.716914-1-ebiggers@kernel.org Signed-off-by: Eric Biggers ebiggers@kernel.org --- arch/arm/crypto/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/crypto/Kconfig b/arch/arm/crypto/Kconfig index c46c05548080..c5d676e7f16b 100644 --- a/arch/arm/crypto/Kconfig +++ b/arch/arm/crypto/Kconfig @@ -145,10 +145,10 @@ config CRYPTO_NHPOLY1305_NEON depends on KERNEL_MODE_NEON select CRYPTO_NHPOLY1305

config CRYPTO_CURVE25519_NEON tristate "NEON accelerated Curve25519 scalar multiplication library" - depends on KERNEL_MODE_NEON + depends on KERNEL_MODE_NEON && !CPU_BIG_ENDIAN select CRYPTO_LIB_CURVE25519_GENERIC select CRYPTO_ARCH_HAVE_LIB_CURVE25519

endif

base-commit: df70e44fa05b01476a78d0f6a210354784ff0992