FROMGIT: crypto: arm/chacha - add XChaCha12 support

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 12 instead of 20.

XChaCha12 is faster than XChaCha20 but has a lower security margin,
though still greater than AES-256's since the best known attacks make it
through only 7 rounds.  See the patch "crypto: chacha - add XChaCha12
support" for more details about why we need XChaCha12 support.

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>
(cherry picked from commit bdb063a79f6da589af1de3f10a7c8f654fba9ae8
 https://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git master)
Bug: 112008522
Test: As series, see Ic61c13b53facfd2173065be715a7ee5f3af8760b
Change-Id: I08fba7f6f8bc9f1d08a75f5e6f6b73ceba6b8109
Signed-off-by: Eric Biggers <ebiggers@google.com>

diff --git a/arch/arm/crypto/Kconfig b/arch/arm/crypto/Kconfig
index 686eae8c93555af58a56a0d16a3fd73b581373cb..8284a40edf5aa91ce1474151391c72445a78b83c 100644 (file)
--- a/arch/arm/crypto/Kconfig
+++ b/arch/arm/crypto/Kconfig
@@ -125,7 +125,7 @@ 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 385557d3863418d46d1e21e93a86a454235d3092..9d6fda81986da6b4e3470ebcb2ded59f7a6966e8 100644 (file)
--- 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. <ard.biesheuvel@linaro.org>
  *
@@ -154,6 +155,22 @@ 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,
        }
 };
 
@@ -180,3 +197,5 @@ 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");