[PATCH] crypto: x86/aesni: Align the address before aes_set_key_common()

Chang S. Bae
2023-06-21T12:19:46Z

aes_set_key_common() performs runtime alignment to the void *raw_ctx
pointer. This facilitates consistent access to the 16byte-aligned
address during key extension.

However, the alignment is already handlded in the GCM-related setkey
functions before invoking the common function. Consequently, the
alignment in the common function is unnecessary for those functions.

To establish a consistent approach throughout the glue code, remove
the aes_ctx() call from its current location. Instead, place it at
each call site where the runtime alignment is currently absent.

Link: https://lore.kernel.org/lkml/20230605024623.GA4653@quark.localdomain/
Suggested-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Cc: linux-crypto@vger.kernel.org
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
---
The need for this fix was discovered during Eric's review of the Key
Locker series [1]. Considering the upstream code also requires this
improvement, this is applicable regardless of the Key Locker enabling
[2].

[1] https://lore.kernel.org/lkml/20230605024623.GA4653@quark.localdomain/
[2] https://lore.kernel.org/lkml/f1093780-cdda-35ec-3ef1-e5fab4139bef@intel.com/
---
arch/x86/crypto/aesni-intel_glue.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/crypto/aesni-intel_glue.c b/arch/x86/crypto/aesni-intel_glue.c
index a5b0cb3efeba..c4eea7e746e7 100644
--- a/arch/x86/crypto/aesni-intel_glue.c
+++ b/arch/x86/crypto/aesni-intel_glue.c
@@ -229,10 +229,10 @@ static inline struct crypto_aes_ctx *aes_ctx(void *raw_ctx)
return (struct crypto_aes_ctx *)ALIGN(addr, align);
}

-static int aes_set_key_common(struct crypto_tfm *tfm, void *raw_ctx,
+static int aes_set_key_common(struct crypto_tfm *tfm,
+ struct crypto_aes_ctx *ctx,
const u8 *in_key, unsigned int key_len)
{
- struct crypto_aes_ctx *ctx = aes_ctx(raw_ctx);
int err;

if (key_len != AES_KEYSIZE_128 && key_len != AES_KEYSIZE_192 &&
@@ -253,7 +253,7 @@ static int aes_set_key_common(struct crypto_tfm *tfm, void *raw_ctx,
static int aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
unsigned int key_len)
{
- return aes_set_key_common(tfm, crypto_tfm_ctx(tfm), in_key, key_len);
+ return aes_set_key_common(tfm, aes_ctx(crypto_tfm_ctx(tfm)), in_key, key_len);
}

static void aesni_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
@@ -286,7 +286,7 @@ static int aesni_skcipher_setkey(struct crypto_skcipher *tfm, const u8 *key,
unsigned int len)
{
return aes_set_key_common(crypto_skcipher_tfm(tfm),
- crypto_skcipher_ctx(tfm), key, len);
+ aes_ctx(crypto_skcipher_ctx(tfm)), key, len);
}

static int ecb_encrypt(struct skcipher_request *req)
@@ -893,13 +893,13 @@ 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), aes_ctx(ctx->raw_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), aes_ctx(ctx->raw_tweak_ctx),
key + keylen, keylen);
}

--
2.34.1