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Message-ID: <20210720085535.141486-9-tudor.ambarus@microchip.com>
Date: Tue, 20 Jul 2021 11:55:34 +0300
From: Tudor Ambarus <tudor.ambarus@...rochip.com>
To: <herbert@...dor.apana.org.au>
CC: <nicolas.ferre@...rochip.com>, <alexandre.belloni@...tlin.com>,
<ludovic.desroches@...rochip.com>, <linux-crypto@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>,
"Tudor Ambarus" <tudor.ambarus@...rochip.com>
Subject: [PATCH 8/9] crypto: atmel-aes: Add fallback to XTS software implementation
XTS is supported just for input lengths with data units of 128-bit blocks.
Add a fallback to software implementation when the last block is shorter
than 128 bits.
Signed-off-by: Tudor Ambarus <tudor.ambarus@...rochip.com>
---
drivers/crypto/atmel-aes.c | 55 +++++++++++++++++++++++++++++++++++---
1 file changed, 51 insertions(+), 4 deletions(-)
diff --git a/drivers/crypto/atmel-aes.c b/drivers/crypto/atmel-aes.c
index 9ec007b4f8fc..e74fcaac551e 100644
--- a/drivers/crypto/atmel-aes.c
+++ b/drivers/crypto/atmel-aes.c
@@ -143,6 +143,7 @@ struct atmel_aes_xts_ctx {
struct atmel_aes_base_ctx base;
u32 key2[AES_KEYSIZE_256 / sizeof(u32)];
+ struct crypto_skcipher *fallback_tfm;
};
#if IS_ENABLED(CONFIG_CRYPTO_DEV_ATMEL_AUTHENC)
@@ -155,6 +156,7 @@ struct atmel_aes_authenc_ctx {
struct atmel_aes_reqctx {
unsigned long mode;
u8 lastc[AES_BLOCK_SIZE];
+ struct skcipher_request fallback_req;
};
#if IS_ENABLED(CONFIG_CRYPTO_DEV_ATMEL_AUTHENC)
@@ -1083,6 +1085,22 @@ static int atmel_aes_ctr_start(struct atmel_aes_dev *dd)
return atmel_aes_ctr_transfer(dd);
}
+static int atmel_aes_xts_fallback(struct skcipher_request *req, bool enc)
+{
+ struct atmel_aes_reqctx *rctx = skcipher_request_ctx(req);
+ struct atmel_aes_xts_ctx *ctx = crypto_skcipher_ctx(
+ crypto_skcipher_reqtfm(req));
+
+ skcipher_request_set_tfm(&rctx->fallback_req, ctx->fallback_tfm);
+ skcipher_request_set_callback(&rctx->fallback_req, req->base.flags,
+ req->base.complete, req->base.data);
+ skcipher_request_set_crypt(&rctx->fallback_req, req->src, req->dst,
+ req->cryptlen, req->iv);
+
+ return enc ? crypto_skcipher_encrypt(&rctx->fallback_req) :
+ crypto_skcipher_decrypt(&rctx->fallback_req);
+}
+
static int atmel_aes_crypt(struct skcipher_request *req, unsigned long mode)
{
struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
@@ -1091,8 +1109,14 @@ static int atmel_aes_crypt(struct skcipher_request *req, unsigned long mode)
struct atmel_aes_dev *dd;
u32 opmode = mode & AES_FLAGS_OPMODE_MASK;
- if (opmode == AES_FLAGS_XTS && req->cryptlen < XTS_BLOCK_SIZE)
- return -EINVAL;
+ if (opmode == AES_FLAGS_XTS) {
+ if (req->cryptlen < XTS_BLOCK_SIZE)
+ return -EINVAL;
+
+ if (!IS_ALIGNED(req->cryptlen, XTS_BLOCK_SIZE))
+ return atmel_aes_xts_fallback(req,
+ mode & AES_FLAGS_ENCRYPT);
+ }
/*
* ECB, CBC, CFB, OFB or CTR mode require the plaintext and ciphertext
@@ -1864,6 +1888,13 @@ static int atmel_aes_xts_setkey(struct crypto_skcipher *tfm, const u8 *key,
if (err)
return err;
+ crypto_skcipher_clear_flags(ctx->fallback_tfm, CRYPTO_TFM_REQ_MASK);
+ crypto_skcipher_set_flags(ctx->fallback_tfm, tfm->base.crt_flags &
+ CRYPTO_TFM_REQ_MASK);
+ err = crypto_skcipher_setkey(ctx->fallback_tfm, key, keylen);
+ if (err)
+ return err;
+
memcpy(ctx->base.key, key, keylen/2);
memcpy(ctx->key2, key + keylen/2, keylen/2);
ctx->base.keylen = keylen/2;
@@ -1884,18 +1915,33 @@ static int atmel_aes_xts_decrypt(struct skcipher_request *req)
static int atmel_aes_xts_init_tfm(struct crypto_skcipher *tfm)
{
struct atmel_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
+ const char *tfm_name = crypto_tfm_alg_name(&tfm->base);
- crypto_skcipher_set_reqsize(tfm, sizeof(struct atmel_aes_reqctx));
+ ctx->fallback_tfm = crypto_alloc_skcipher(tfm_name, 0,
+ CRYPTO_ALG_NEED_FALLBACK);
+ if (IS_ERR(ctx->fallback_tfm))
+ return PTR_ERR(ctx->fallback_tfm);
+
+ crypto_skcipher_set_reqsize(tfm, sizeof(struct atmel_aes_reqctx) +
+ crypto_skcipher_reqsize(ctx->fallback_tfm));
ctx->base.start = atmel_aes_xts_start;
return 0;
}
+static void atmel_aes_xts_exit_tfm(struct crypto_skcipher *tfm)
+{
+ struct atmel_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
+
+ crypto_free_skcipher(ctx->fallback_tfm);
+}
+
static struct skcipher_alg aes_xts_alg = {
.base.cra_name = "xts(aes)",
.base.cra_driver_name = "atmel-xts-aes",
.base.cra_blocksize = AES_BLOCK_SIZE,
.base.cra_ctxsize = sizeof(struct atmel_aes_xts_ctx),
+ .base.cra_flags = CRYPTO_ALG_NEED_FALLBACK,
.min_keysize = 2 * AES_MIN_KEY_SIZE,
.max_keysize = 2 * AES_MAX_KEY_SIZE,
@@ -1904,6 +1950,7 @@ static struct skcipher_alg aes_xts_alg = {
.encrypt = atmel_aes_xts_encrypt,
.decrypt = atmel_aes_xts_decrypt,
.init = atmel_aes_xts_init_tfm,
+ .exit = atmel_aes_xts_exit_tfm,
};
#if IS_ENABLED(CONFIG_CRYPTO_DEV_ATMEL_AUTHENC)
@@ -2373,7 +2420,7 @@ static void atmel_aes_unregister_algs(struct atmel_aes_dev *dd)
static void atmel_aes_crypto_alg_init(struct crypto_alg *alg)
{
- alg->cra_flags = CRYPTO_ALG_ASYNC;
+ alg->cra_flags |= CRYPTO_ALG_ASYNC;
alg->cra_alignmask = 0xf;
alg->cra_priority = ATMEL_AES_PRIORITY;
alg->cra_module = THIS_MODULE;
--
2.25.1
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