crypto: chacha20-generic - refactor to allow varying number of rounds

In preparation for adding XChaCha12 support, rename/refactor
chacha20-generic to support different numbers of rounds.  The
justification for needing XChaCha12 support is explained in more detail
in the patch "crypto: chacha - add XChaCha12 support".

The only difference between ChaCha{8,12,20} are the number of rounds
itself; all other parts of the algorithm are the same.  Therefore,
remove the "20" from all definitions, structures, functions, files, etc.
that will be shared by all ChaCha versions.

Also make ->setkey() store the round count in the chacha_ctx (previously
chacha20_ctx).  The generic code then passes the round count through to
chacha_block().  There will be a ->setkey() function for each explicitly
allowed round count; the encrypt/decrypt functions will be the same.  I
decided not to do it the opposite way (same ->setkey() function for all
round counts, with different encrypt/decrypt functions) because that
would have required more boilerplate code in architecture-specific
implementations of ChaCha and XChaCha.

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

1 files changed, 20 insertions, 20 deletions

diff --git a/arch/arm/crypto/chacha20-neon-glue.c b/arch/arm/crypto/chacha20-neon-glue.c
index 59a7be08e80c..7386eb1c1889 100644
--- a/arch/arm/crypto/chacha20-neon-glue.c
+++ b/arch/arm/crypto/chacha20-neon-glue.c
@@ -19,7 +19,7 @@
  */
 
 #include <crypto/algapi.h>
-#include <crypto/chacha20.h>
+#include <crypto/chacha.h>
 #include <crypto/internal/skcipher.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -34,20 +34,20 @@ asmlinkage void chacha20_4block_xor_neon(u32 *state, u8 *dst, const u8 *src);
 static void chacha20_doneon(u32 *state, u8 *dst, const u8 *src,
 			    unsigned int bytes)
 {
-	u8 buf[CHACHA20_BLOCK_SIZE];
+	u8 buf[CHACHA_BLOCK_SIZE];
 
-	while (bytes >= CHACHA20_BLOCK_SIZE * 4) {
+	while (bytes >= CHACHA_BLOCK_SIZE * 4) {
 		chacha20_4block_xor_neon(state, dst, src);
-		bytes -= CHACHA20_BLOCK_SIZE * 4;
-		src += CHACHA20_BLOCK_SIZE * 4;
-		dst += CHACHA20_BLOCK_SIZE * 4;
+		bytes -= CHACHA_BLOCK_SIZE * 4;
+		src += CHACHA_BLOCK_SIZE * 4;
+		dst += CHACHA_BLOCK_SIZE * 4;
 		state[12] += 4;
 	}
-	while (bytes >= CHACHA20_BLOCK_SIZE) {
+	while (bytes >= CHACHA_BLOCK_SIZE) {
 		chacha20_block_xor_neon(state, dst, src);
-		bytes -= CHACHA20_BLOCK_SIZE;
-		src += CHACHA20_BLOCK_SIZE;
-		dst += CHACHA20_BLOCK_SIZE;
+		bytes -= CHACHA_BLOCK_SIZE;
+		src += CHACHA_BLOCK_SIZE;
+		dst += CHACHA_BLOCK_SIZE;
 		state[12]++;
 	}
 	if (bytes) {
@@ -60,17 +60,17 @@ static void chacha20_doneon(u32 *state, u8 *dst, const u8 *src,
 static int chacha20_neon(struct skcipher_request *req)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
-	struct chacha20_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
 	struct skcipher_walk walk;
 	u32 state[16];
 	int err;
 
-	if (req->cryptlen <= CHACHA20_BLOCK_SIZE || !may_use_simd())
-		return crypto_chacha20_crypt(req);
+	if (req->cryptlen <= CHACHA_BLOCK_SIZE || !may_use_simd())
+		return crypto_chacha_crypt(req);
 
 	err = skcipher_walk_virt(&walk, req, true);
 
-	crypto_chacha20_init(state, ctx, walk.iv);
+	crypto_chacha_init(state, ctx, walk.iv);
 
 	kernel_neon_begin();
 	while (walk.nbytes > 0) {
@@ -93,14 +93,14 @@ static struct skcipher_alg alg = {
 	.base.cra_driver_name	= "chacha20-neon",
 	.base.cra_priority	= 300,
 	.base.cra_blocksize	= 1,
-	.base.cra_ctxsize	= sizeof(struct chacha20_ctx),
+	.base.cra_ctxsize	= sizeof(struct chacha_ctx),
 	.base.cra_module	= THIS_MODULE,
 
-	.min_keysize		= CHACHA20_KEY_SIZE,
-	.max_keysize		= CHACHA20_KEY_SIZE,
-	.ivsize			= CHACHA20_IV_SIZE,
-	.chunksize		= CHACHA20_BLOCK_SIZE,
-	.walksize		= 4 * CHACHA20_BLOCK_SIZE,
+	.min_keysize		= CHACHA_KEY_SIZE,
+	.max_keysize		= CHACHA_KEY_SIZE,
+	.ivsize			= CHACHA_IV_SIZE,
+	.chunksize		= CHACHA_BLOCK_SIZE,
+	.walksize		= 4 * CHACHA_BLOCK_SIZE,
 	.setkey			= crypto_chacha20_setkey,
 	.encrypt		= chacha20_neon,
 	.decrypt		= chacha20_neon,