[PATCH v7 10/12] crypto: x86/aesni - Use the proper data type in struct aesni_xts_ctx

[Chang S. Bae]

Every field in struct aesni_xts_ctx is a pointer to a byte array. Each
array has a size of struct crypto_aes_ctx. Then, the field can be
redefined as that struct type instead of the obscure pointer.

Subsequently, the address to struct aesni_xts_ctx should be aligned
right away. This can also simplify the runtime alignment code.

Redefine struct aesni_xts_ctx, and align its address on the front.
This draws a rework by refactoring the common alignment code. Then,
clean up the alignment for the old pointers.

Suggested-by: Eric Biggers <ebiggers@xxxxxxxxxx>
Signed-off-by: Chang S. Bae <chang.seok.bae@xxxxxxxxx>
Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Eric Biggers <ebiggers@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: linux-crypto@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
Changes from v6:
* Add as a new patch. (Eric Biggers)

This fix was considered to be better addressed before the preparatory
AES-NI code rework.
---
 arch/x86/crypto/aesni-intel_glue.c | 38 +++++++++++++++++-------------
 1 file changed, 22 insertions(+), 16 deletions(-)

diff --git a/arch/x86/crypto/aesni-intel_glue.c b/arch/x86/crypto/aesni-intel_glue.c
index a5b0cb3efeba..97a1629b84c4 100644
--- a/arch/x86/crypto/aesni-intel_glue.c
+++ b/arch/x86/crypto/aesni-intel_glue.c
@@ -61,8 +61,8 @@ struct generic_gcmaes_ctx {
 };
 
 struct aesni_xts_ctx {
-	u8 raw_tweak_ctx[sizeof(struct crypto_aes_ctx)] AESNI_ALIGN_ATTR;
-	u8 raw_crypt_ctx[sizeof(struct crypto_aes_ctx)] AESNI_ALIGN_ATTR;
+	struct crypto_aes_ctx tweak_ctx AESNI_ALIGN_ATTR;
+	struct crypto_aes_ctx crypt_ctx AESNI_ALIGN_ATTR;
 };
 
 #define GCM_BLOCK_LEN 16
@@ -219,14 +219,20 @@ generic_gcmaes_ctx *generic_gcmaes_ctx_get(struct crypto_aead *tfm)
 }
 #endif
 
+static inline unsigned long aes_align_addr(unsigned long addr)
+{
+	return (crypto_tfm_ctx_alignment() >= AESNI_ALIGN) ?
+	       ALIGN(addr, 1) : ALIGN(addr, AESNI_ALIGN);
+}
+
 static inline struct crypto_aes_ctx *aes_ctx(void *raw_ctx)
 {
-	unsigned long addr = (unsigned long)raw_ctx;
-	unsigned long align = AESNI_ALIGN;
+	return (struct crypto_aes_ctx *)aes_align_addr((unsigned long)raw_ctx);
+}
 
-	if (align <= crypto_tfm_ctx_alignment())
-		align = 1;
-	return (struct crypto_aes_ctx *)ALIGN(addr, align);
+static inline struct aesni_xts_ctx *aes_xts_ctx(struct crypto_skcipher *tfm)
+{
+	return (struct aesni_xts_ctx *)aes_align_addr((unsigned long)crypto_skcipher_ctx(tfm));
 }
 
 static int aes_set_key_common(struct crypto_tfm *tfm, void *raw_ctx,
@@ -883,7 +889,7 @@ static int helper_rfc4106_decrypt(struct aead_request *req)
 static int xts_aesni_setkey(struct crypto_skcipher *tfm, const u8 *key,
 			    unsigned int keylen)
 {
-	struct aesni_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct aesni_xts_ctx *ctx = aes_xts_ctx(tfm);
 	int err;
 
 	err = xts_verify_key(tfm, key, keylen);
@@ -893,20 +899,20 @@ static int xts_aesni_setkey(struct crypto_skcipher *tfm, const u8 *key,
 	keylen /= 2;
 
 	/* first half of xts-key is for crypt */
-	err = aes_set_key_common(crypto_skcipher_tfm(tfm), ctx->raw_crypt_ctx,
+	err = aes_set_key_common(crypto_skcipher_tfm(tfm), &ctx->crypt_ctx,
 				 key, keylen);
 	if (err)
 		return err;
 
 	/* second half of xts-key is for tweak */
-	return aes_set_key_common(crypto_skcipher_tfm(tfm), ctx->raw_tweak_ctx,
+	return aes_set_key_common(crypto_skcipher_tfm(tfm), &ctx->tweak_ctx,
 				  key + keylen, keylen);
 }
 
 static int xts_crypt(struct skcipher_request *req, bool encrypt)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
-	struct aesni_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct aesni_xts_ctx *ctx = aes_xts_ctx(tfm);
 	int tail = req->cryptlen % AES_BLOCK_SIZE;
 	struct skcipher_request subreq;
 	struct skcipher_walk walk;
@@ -942,7 +948,7 @@ static int xts_crypt(struct skcipher_request *req, bool encrypt)
 	kernel_fpu_begin();
 
 	/* calculate first value of T */
-	aesni_enc(aes_ctx(ctx->raw_tweak_ctx), walk.iv, walk.iv);
+	aesni_enc(&ctx->tweak_ctx, walk.iv, walk.iv);
 
 	while (walk.nbytes > 0) {
 		int nbytes = walk.nbytes;
@@ -951,11 +957,11 @@ static int xts_crypt(struct skcipher_request *req, bool encrypt)
 			nbytes &= ~(AES_BLOCK_SIZE - 1);
 
 		if (encrypt)
-			aesni_xts_encrypt(aes_ctx(ctx->raw_crypt_ctx),
+			aesni_xts_encrypt(&ctx->crypt_ctx,
 					  walk.dst.virt.addr, walk.src.virt.addr,
 					  nbytes, walk.iv);
 		else
-			aesni_xts_decrypt(aes_ctx(ctx->raw_crypt_ctx),
+			aesni_xts_decrypt(&ctx->crypt_ctx,
 					  walk.dst.virt.addr, walk.src.virt.addr,
 					  nbytes, walk.iv);
 		kernel_fpu_end();
@@ -983,11 +989,11 @@ static int xts_crypt(struct skcipher_request *req, bool encrypt)
 
 		kernel_fpu_begin();
 		if (encrypt)
-			aesni_xts_encrypt(aes_ctx(ctx->raw_crypt_ctx),
+			aesni_xts_encrypt(&ctx->crypt_ctx,
 					  walk.dst.virt.addr, walk.src.virt.addr,
 					  walk.nbytes, walk.iv);
 		else
-			aesni_xts_decrypt(aes_ctx(ctx->raw_crypt_ctx),
+			aesni_xts_decrypt(&ctx->crypt_ctx,
 					  walk.dst.virt.addr, walk.src.virt.addr,
 					  walk.nbytes, walk.iv);
 		kernel_fpu_end();
-- 
2.17.1