From: Eric Biggers Subject: [RFC PATCH 7/9] crypto: arm/chacha - add XChaCha12 support Date: Mon, 6 Aug 2018 15:32:58 -0700 Message-ID: <20180806223300.113891-8-ebiggers@kernel.org> References: <20180806223300.113891-1-ebiggers@kernel.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Cc: linux-fscrypt@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Herbert Xu , Paul Crowley , Greg Kaiser , Michael Halcrow , "Jason A . Donenfeld" , Samuel Neves , Tomer Ashur , Eric Biggers To: linux-crypto@vger.kernel.org Return-path: In-Reply-To: <20180806223300.113891-1-ebiggers@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org From: Eric Biggers Now that the 32-bit ARM NEON implementation of ChaCha20 and XChaCha20 has been refactored to support varying the number of rounds, add support for XChaCha12. This is identical to XChaCha20 except for the number of rounds, which is reduced from 20 to 12. As I explained in more detail in the patch which added XChaCha12 to the generic code, "crypto: chacha - add XChaCha12 support", we'd prefer to use XChaCha20, but unfortunately it is not fast enough for our use case. Thus, we must settle for a reduced-round variant. See that patch for a more detailed explanation. Signed-off-by: Eric Biggers --- arch/arm/crypto/Kconfig | 2 +- arch/arm/crypto/chacha-neon-glue.c | 21 ++++++++++++++++++++- 2 files changed, 21 insertions(+), 2 deletions(-) diff --git a/arch/arm/crypto/Kconfig b/arch/arm/crypto/Kconfig index 896dcf142719..75c613413e31 100644 --- a/arch/arm/crypto/Kconfig +++ b/arch/arm/crypto/Kconfig @@ -116,7 +116,7 @@ config CRYPTO_CRC32_ARM_CE select CRYPTO_HASH config CRYPTO_CHACHA20_NEON - tristate "NEON accelerated ChaCha20 stream cipher algorithms" + tristate "NEON accelerated ChaCha stream cipher algorithms" depends on KERNEL_MODE_NEON select CRYPTO_BLKCIPHER select CRYPTO_CHACHA20 diff --git a/arch/arm/crypto/chacha-neon-glue.c b/arch/arm/crypto/chacha-neon-glue.c index b236af4889c6..0b1b23822770 100644 --- a/arch/arm/crypto/chacha-neon-glue.c +++ b/arch/arm/crypto/chacha-neon-glue.c @@ -1,5 +1,6 @@ /* - * ChaCha20 (RFC7539) and XChaCha20 stream ciphers, NEON accelerated + * ARM NEON accelerated ChaCha and XChaCha stream ciphers, + * including ChaCha20 (RFC7539) * * Copyright (C) 2016 Linaro, Ltd. * @@ -160,6 +161,22 @@ static struct skcipher_alg algs[] = { .setkey = crypto_chacha20_setkey, .encrypt = xchacha_neon, .decrypt = xchacha_neon, + }, { + .base.cra_name = "xchacha12", + .base.cra_driver_name = "xchacha12-neon", + .base.cra_priority = 300, + .base.cra_blocksize = 1, + .base.cra_ctxsize = sizeof(struct chacha_ctx), + .base.cra_module = THIS_MODULE, + + .min_keysize = CHACHA_KEY_SIZE, + .max_keysize = CHACHA_KEY_SIZE, + .ivsize = XCHACHA_IV_SIZE, + .chunksize = CHACHA_BLOCK_SIZE, + .walksize = 4 * CHACHA_BLOCK_SIZE, + .setkey = crypto_chacha12_setkey, + .encrypt = xchacha_neon, + .decrypt = xchacha_neon, } }; @@ -186,3 +203,5 @@ MODULE_ALIAS_CRYPTO("chacha20"); MODULE_ALIAS_CRYPTO("chacha20-neon"); MODULE_ALIAS_CRYPTO("xchacha20"); MODULE_ALIAS_CRYPTO("xchacha20-neon"); +MODULE_ALIAS_CRYPTO("xchacha12"); +MODULE_ALIAS_CRYPTO("xchacha12-neon"); -- 2.18.0.597.ga71716f1ad-goog