crypto: arm64/chacha - add XChaCha12 support

Now that the ARM64 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 12 instead of 20.  This can be used by Adiantum.

Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/arch/arm64/crypto/Kconfig b/arch/arm64/crypto/Kconfig
index d54ddb8..d9a523e 100644 (file)
--- a/arch/arm64/crypto/Kconfig
+++ b/arch/arm64/crypto/Kconfig
@@ -101,7 +101,7 @@ config CRYPTO_AES_ARM64_NEON_BLK
        select CRYPTO_SIMD
 
 config CRYPTO_CHACHA20_NEON
-       tristate "ChaCha20 and XChaCha20 stream ciphers using NEON instructions"
+       tristate "ChaCha20, XChaCha20, and XChaCha12 stream ciphers using NEON instructions"
        depends on KERNEL_MODE_NEON
        select CRYPTO_BLKCIPHER
        select CRYPTO_CHACHA20

diff --git a/arch/arm64/crypto/chacha-neon-glue.c b/arch/arm64/crypto/chacha-neon-glue.c
index 4d99202..346eb85 100644 (file)
--- a/arch/arm64/crypto/chacha-neon-glue.c
+++ b/arch/arm64/crypto/chacha-neon-glue.c
@@ -161,6 +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,
        }
 };
 
@@ -187,3 +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");