[v3 PATCH 4/31] crypto: arm64/aes-glue - Add support for chaining CTS

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As it stands cts cannot do chaining.  That is, it always performs
the cipher-text stealing at the end of a request.  This patch adds
support for chaining when the CRYPTO_TM_REQ_MORE flag is set.

It also sets the final_chunksize so that data can be withheld by
the caller to enable correct processing at the true end of a request.

Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
---

 arch/arm64/crypto/aes-glue.c |   17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/crypto/aes-glue.c b/arch/arm64/crypto/aes-glue.c
index 395bbf64b2abb..f63feb00e354d 100644
--- a/arch/arm64/crypto/aes-glue.c
+++ b/arch/arm64/crypto/aes-glue.c
@@ -283,11 +283,15 @@ static int cts_cbc_encrypt(struct skcipher_request *req)
 	skcipher_request_set_callback(&subreq, skcipher_request_flags(req),
 				      NULL, NULL);
 
-	if (req->cryptlen <= AES_BLOCK_SIZE) {
-		if (req->cryptlen < AES_BLOCK_SIZE)
+	if (req->cryptlen < AES_BLOCK_SIZE)
+		return -EINVAL;
+
+	if (req->base.flags & CRYPTO_TFM_REQ_MORE) {
+		if (req->cryptlen & (AES_BLOCK_SIZE - 1))
 			return -EINVAL;
+		cbc_blocks += 2;
+	} else if (req->cryptlen == AES_BLOCK_SIZE)
 		cbc_blocks = 1;
-	}
 
 	if (cbc_blocks > 0) {
 		skcipher_request_set_crypt(&subreq, req->src, req->dst,
@@ -299,7 +303,8 @@ static int cts_cbc_encrypt(struct skcipher_request *req)
 		if (err)
 			return err;
 
-		if (req->cryptlen == AES_BLOCK_SIZE)
+		if (req->cryptlen == AES_BLOCK_SIZE ||
+		    req->base.flags & CRYPTO_TFM_REQ_MORE)
 			return 0;
 
 		dst = src = scatterwalk_ffwd(sg_src, req->src, subreq.cryptlen);
@@ -738,13 +743,15 @@ static struct skcipher_alg aes_algs[] = { {
 		.cra_driver_name	= "__cts-cbc-aes-" MODE,
 		.cra_priority		= PRIO,
 		.cra_flags		= CRYPTO_ALG_INTERNAL,
-		.cra_blocksize		= AES_BLOCK_SIZE,
+		.cra_blocksize		= 1,
 		.cra_ctxsize		= sizeof(struct crypto_aes_ctx),
 		.cra_module		= THIS_MODULE,
 	},
 	.min_keysize	= AES_MIN_KEY_SIZE,
 	.max_keysize	= AES_MAX_KEY_SIZE,
 	.ivsize		= AES_BLOCK_SIZE,
+	.chunksize	= AES_BLOCK_SIZE,
+	.final_chunksize	= 2 * AES_BLOCK_SIZE,
 	.walksize	= 2 * AES_BLOCK_SIZE,
 	.setkey		= skcipher_aes_setkey,
 	.encrypt	= cts_cbc_encrypt,



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