[PATCH 3/3] crypto: cts - Add support for chaining

["Herbert Xu" <herbert@gondor.apana.org.au>]

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 fcsize 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@gondor.apana.org.au>
---

 crypto/cts.c |   19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/crypto/cts.c b/crypto/cts.c
index 5e005c4f02215..3cca3112e7dca 100644
--- a/crypto/cts.c
+++ b/crypto/cts.c
@@ -100,7 +100,7 @@ static int cts_cbc_encrypt(struct skcipher_request *req)
 	struct crypto_cts_reqctx *rctx = skcipher_request_ctx(req);
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct skcipher_request *subreq = &rctx->subreq;
-	int bsize = crypto_skcipher_blocksize(tfm);
+	int bsize = crypto_skcipher_chunksize(tfm);
 	u8 d[MAX_CIPHER_BLOCKSIZE * 2] __aligned(__alignof__(u32));
 	struct scatterlist *sg;
 	unsigned int offset;
@@ -146,7 +146,7 @@ static int crypto_cts_encrypt(struct skcipher_request *req)
 	struct crypto_cts_reqctx *rctx = skcipher_request_ctx(req);
 	struct crypto_cts_ctx *ctx = crypto_skcipher_ctx(tfm);
 	struct skcipher_request *subreq = &rctx->subreq;
-	int bsize = crypto_skcipher_blocksize(tfm);
+	int bsize = crypto_skcipher_chunksize(tfm);
 	unsigned int nbytes = req->cryptlen;
 	unsigned int offset;
 
@@ -155,7 +155,7 @@ static int crypto_cts_encrypt(struct skcipher_request *req)
 	if (nbytes < bsize)
 		return -EINVAL;
 
-	if (nbytes == bsize) {
+	if (nbytes == bsize || req->base.flags & CRYPTO_TFM_REQ_MORE) {
 		skcipher_request_set_callback(subreq, req->base.flags,
 					      req->base.complete,
 					      req->base.data);
@@ -181,7 +181,7 @@ static int cts_cbc_decrypt(struct skcipher_request *req)
 	struct crypto_cts_reqctx *rctx = skcipher_request_ctx(req);
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct skcipher_request *subreq = &rctx->subreq;
-	int bsize = crypto_skcipher_blocksize(tfm);
+	int bsize = crypto_skcipher_chunksize(tfm);
 	u8 d[MAX_CIPHER_BLOCKSIZE * 2] __aligned(__alignof__(u32));
 	struct scatterlist *sg;
 	unsigned int offset;
@@ -240,7 +240,7 @@ static int crypto_cts_decrypt(struct skcipher_request *req)
 	struct crypto_cts_reqctx *rctx = skcipher_request_ctx(req);
 	struct crypto_cts_ctx *ctx = crypto_skcipher_ctx(tfm);
 	struct skcipher_request *subreq = &rctx->subreq;
-	int bsize = crypto_skcipher_blocksize(tfm);
+	int bsize = crypto_skcipher_chunksize(tfm);
 	unsigned int nbytes = req->cryptlen;
 	unsigned int offset;
 	u8 *space;
@@ -250,7 +250,7 @@ static int crypto_cts_decrypt(struct skcipher_request *req)
 	if (nbytes < bsize)
 		return -EINVAL;
 
-	if (nbytes == bsize) {
+	if (nbytes == bsize || req->base.flags & CRYPTO_TFM_REQ_MORE) {
 		skcipher_request_set_callback(subreq, req->base.flags,
 					      req->base.complete,
 					      req->base.data);
@@ -297,7 +297,7 @@ static int crypto_cts_init_tfm(struct crypto_skcipher *tfm)
 	ctx->child = cipher;
 
 	align = crypto_skcipher_alignmask(tfm);
-	bsize = crypto_skcipher_blocksize(cipher);
+	bsize = crypto_skcipher_chunksize(cipher);
 	reqsize = ALIGN(sizeof(struct crypto_cts_reqctx) +
 			crypto_skcipher_reqsize(cipher),
 			crypto_tfm_ctx_alignment()) +
@@ -366,11 +366,12 @@ static int crypto_cts_create(struct crypto_template *tmpl, struct rtattr **tb)
 
 	inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
 	inst->alg.base.cra_priority = alg->base.cra_priority;
-	inst->alg.base.cra_blocksize = alg->base.cra_blocksize;
+	inst->alg.base.cra_blocksize = 1;
 	inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
 
 	inst->alg.ivsize = alg->base.cra_blocksize;
-	inst->alg.chunksize = crypto_skcipher_alg_chunksize(alg);
+	inst->alg.chunksize = alg->base.cra_blocksize;
+	inst->alg.fcsize = inst->alg.chunksize * 2;
 	inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg);
 	inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg);