[RFC PATCH 12/20] crypto: arm64/aes-ccm - switch to AES library

From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: linux-crypto@vger.kernel.org
Cc: herbert@gondor.apana.org.au, ebiggers@kernel.org,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>
Subject: [RFC PATCH 12/20] crypto: arm64/aes-ccm - switch to AES library
Date: Wed, 12 Jun 2019 14:48:30 +0200	[thread overview]
Message-ID: <20190612124838.2492-13-ard.biesheuvel@linaro.org> (raw)
In-Reply-To: <20190612124838.2492-1-ard.biesheuvel@linaro.org>

The CCM code calls directly into the scalar table based AES cipher for
arm64 from the fallback path, and since this implementation is known to
be non-time invariant, doing so from a time invariant SIMD cipher is a
bit nasty.

So let's switch to the AES library - this makes the code more robust,
and drops the dependency on the generic AES cipher, allowing us to
omit it entirely in the future.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/arm64/crypto/Kconfig           |  2 +-
 arch/arm64/crypto/aes-ce-ccm-glue.c | 18 ++++++------------
 2 files changed, 7 insertions(+), 13 deletions(-)

diff --git a/arch/arm64/crypto/Kconfig b/arch/arm64/crypto/Kconfig
index 1762055e7093..c6032bfb44fb 100644
--- a/arch/arm64/crypto/Kconfig
+++ b/arch/arm64/crypto/Kconfig
@@ -80,8 +80,8 @@ config CRYPTO_AES_ARM64_CE_CCM
 	depends on ARM64 && KERNEL_MODE_NEON
 	select CRYPTO_ALGAPI
 	select CRYPTO_AES_ARM64_CE
-	select CRYPTO_AES_ARM64
 	select CRYPTO_AEAD
+	select CRYPTO_LIB_AES
 
 config CRYPTO_AES_ARM64_CE_BLK
 	tristate "AES in ECB/CBC/CTR/XTS modes using ARMv8 Crypto Extensions"
diff --git a/arch/arm64/crypto/aes-ce-ccm-glue.c b/arch/arm64/crypto/aes-ce-ccm-glue.c
index cb89c80800b5..b9b7cf4b5a8f 100644
--- a/arch/arm64/crypto/aes-ce-ccm-glue.c
+++ b/arch/arm64/crypto/aes-ce-ccm-glue.c
@@ -46,8 +46,6 @@ asmlinkage void ce_aes_ccm_decrypt(u8 out[], u8 const in[], u32 cbytes,
 asmlinkage void ce_aes_ccm_final(u8 mac[], u8 const ctr[], u32 const rk[],
 				 u32 rounds);
 
-asmlinkage void __aes_arm64_encrypt(u32 *rk, u8 *out, const u8 *in, int rounds);
-
 static int ccm_setkey(struct crypto_aead *tfm, const u8 *in_key,
 		      unsigned int key_len)
 {
@@ -127,8 +125,7 @@ static void ccm_update_mac(struct crypto_aes_ctx *key, u8 mac[], u8 const in[],
 		}
 
 		while (abytes >= AES_BLOCK_SIZE) {
-			__aes_arm64_encrypt(key->key_enc, mac, mac,
-					    num_rounds(key));
+			aes_encrypt(key, mac, mac);
 			crypto_xor(mac, in, AES_BLOCK_SIZE);
 
 			in += AES_BLOCK_SIZE;
@@ -136,8 +133,7 @@ static void ccm_update_mac(struct crypto_aes_ctx *key, u8 mac[], u8 const in[],
 		}
 
 		if (abytes > 0) {
-			__aes_arm64_encrypt(key->key_enc, mac, mac,
-					    num_rounds(key));
+			aes_encrypt(key, mac, mac);
 			crypto_xor(mac, in, abytes);
 			*macp = abytes;
 		}
@@ -209,10 +205,8 @@ static int ccm_crypt_fallback(struct skcipher_walk *walk, u8 mac[], u8 iv0[],
 				bsize = nbytes;
 
 			crypto_inc(walk->iv, AES_BLOCK_SIZE);
-			__aes_arm64_encrypt(ctx->key_enc, buf, walk->iv,
-					    num_rounds(ctx));
-			__aes_arm64_encrypt(ctx->key_enc, mac, mac,
-					    num_rounds(ctx));
+			aes_encrypt(ctx, buf, walk->iv);
+			aes_encrypt(ctx, mac, mac);
 			if (enc)
 				crypto_xor(mac, src, bsize);
 			crypto_xor_cpy(dst, src, buf, bsize);
@@ -227,8 +221,8 @@ static int ccm_crypt_fallback(struct skcipher_walk *walk, u8 mac[], u8 iv0[],
 	}
 
 	if (!err) {
-		__aes_arm64_encrypt(ctx->key_enc, buf, iv0, num_rounds(ctx));
-		__aes_arm64_encrypt(ctx->key_enc, mac, mac, num_rounds(ctx));
+		aes_encrypt(ctx, buf, iv0);
+		aes_encrypt(ctx, mac, mac);
 		crypto_xor(mac, buf, AES_BLOCK_SIZE);
 	}
 	return err;
-- 
2.20.1

