[PATCH v2 6/6] crypto: x86/chacha - add XChaCha12 support

Eric Biggers
2018-11-30T10:10:35Z

From: Eric Biggers <ebiggers@google.com>

Now that the x86_64 SIMD implementations of ChaCha20 and XChaCha20 have
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 12 instead of 20. This can be used by Adiantum.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
arch/x86/crypto/chacha_glue.c | 17 +++++++++++++++++
crypto/Kconfig | 4 ++--
2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/arch/x86/crypto/chacha_glue.c b/arch/x86/crypto/chacha_glue.c
index 83cfb450b816..3db775852205 100644
--- a/arch/x86/crypto/chacha_glue.c
+++ b/arch/x86/crypto/chacha_glue.c
@@ -225,6 +225,21 @@ static struct skcipher_alg algs[] = {
.setkey = crypto_chacha20_setkey,
.encrypt = xchacha_simd,
.decrypt = xchacha_simd,
+ }, {
+ .base.cra_name = "xchacha12",
+ .base.cra_driver_name = "xchacha12-simd",
+ .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,
+ .setkey = crypto_chacha12_setkey,
+ .encrypt = xchacha_simd,
+ .decrypt = xchacha_simd,
},
};

@@ -261,3 +276,5 @@ MODULE_ALIAS_CRYPTO("chacha20");
MODULE_ALIAS_CRYPTO("chacha20-simd");
MODULE_ALIAS_CRYPTO("xchacha20");
MODULE_ALIAS_CRYPTO("xchacha20-simd");
+MODULE_ALIAS_CRYPTO("xchacha12");
+MODULE_ALIAS_CRYPTO("xchacha12-simd");
diff --git a/crypto/Kconfig b/crypto/Kconfig
index df466771e9bf..29865c599b04 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -1473,8 +1473,8 @@ config CRYPTO_CHACHA20_X86_64
select CRYPTO_BLKCIPHER
select CRYPTO_CHACHA20
help
- SSSE3, AVX2, and AVX-512VL optimized implementations of the ChaCha20
- and XChaCha20 stream ciphers.
+ SSSE3, AVX2, and AVX-512VL optimized implementations of the ChaCha20,
+ XChaCha20, and XChaCha12 stream ciphers.

config CRYPTO_SEED
tristate "SEED cipher algorithm"
--
2.20.0.rc0.387.gc7a69e6b6c-goog