[PATCH 12/16] crypto: atmel-aes - Fix saving of IV for CTR mode

[<Tudor.Ambarus@microchip.com>]

From: Tudor Ambarus <tudor.ambarus@microchip.com>

The req->iv of the skcipher_request is expected to contain the
last used IV. Update the req->iv for CTR mode.

Fixes: bd3c7b5c2aba ("crypto: atmel - add Atmel AES driver")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
---
 drivers/crypto/atmel-aes.c | 43 +++++++++++++++++++++++++++++++------------
 1 file changed, 31 insertions(+), 12 deletions(-)

diff --git a/drivers/crypto/atmel-aes.c b/drivers/crypto/atmel-aes.c
index cbfe6ccd2a0d..60f54580d646 100644
--- a/drivers/crypto/atmel-aes.c
+++ b/drivers/crypto/atmel-aes.c
@@ -121,6 +121,7 @@ struct atmel_aes_ctr_ctx {
 	size_t			offset;
 	struct scatterlist	src[2];
 	struct scatterlist	dst[2];
+	u16			blocks;
 };
 
 struct atmel_aes_gcm_ctx {
@@ -513,6 +514,26 @@ static void atmel_aes_set_iv_as_last_ciphertext_block(struct atmel_aes_dev *dd)
 	}
 }
 
+static inline struct atmel_aes_ctr_ctx *
+atmel_aes_ctr_ctx_cast(struct atmel_aes_base_ctx *ctx)
+{
+	return container_of(ctx, struct atmel_aes_ctr_ctx, base);
+}
+
+static void atmel_aes_ctr_update_req_iv(struct atmel_aes_dev *dd)
+{
+	struct atmel_aes_ctr_ctx *ctx = atmel_aes_ctr_ctx_cast(dd->ctx);
+	struct skcipher_request *req = skcipher_request_cast(dd->areq);
+	struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
+	unsigned int ivsize = crypto_skcipher_ivsize(skcipher);
+	int i;
+
+	for (i = 0; i < ctx->blocks; i++)
+		crypto_inc((u8 *)ctx->iv, AES_BLOCK_SIZE);
+
+	memcpy(req->iv, ctx->iv, ivsize);
+}
+
 static inline int atmel_aes_complete(struct atmel_aes_dev *dd, int err)
 {
 	struct skcipher_request *req = skcipher_request_cast(dd->areq);
@@ -527,8 +548,12 @@ static inline int atmel_aes_complete(struct atmel_aes_dev *dd, int err)
 	dd->flags &= ~AES_FLAGS_BUSY;
 
 	if (!dd->ctx->is_aead &&
-	    (rctx->mode & AES_FLAGS_OPMODE_MASK) != AES_FLAGS_ECB)
-		atmel_aes_set_iv_as_last_ciphertext_block(dd);
+	    (rctx->mode & AES_FLAGS_OPMODE_MASK) != AES_FLAGS_ECB) {
+		if ((rctx->mode & AES_FLAGS_OPMODE_MASK) != AES_FLAGS_CTR)
+			atmel_aes_set_iv_as_last_ciphertext_block(dd);
+		else
+			atmel_aes_ctr_update_req_iv(dd);
+	}
 
 	if (dd->is_async)
 		dd->areq->complete(dd->areq, err);
@@ -1007,12 +1032,6 @@ static int atmel_aes_start(struct atmel_aes_dev *dd)
 				   atmel_aes_transfer_complete);
 }
 
-static inline struct atmel_aes_ctr_ctx *
-atmel_aes_ctr_ctx_cast(struct atmel_aes_base_ctx *ctx)
-{
-	return container_of(ctx, struct atmel_aes_ctr_ctx, base);
-}
-
 static int atmel_aes_ctr_transfer(struct atmel_aes_dev *dd)
 {
 	struct atmel_aes_ctr_ctx *ctx = atmel_aes_ctr_ctx_cast(dd->ctx);
@@ -1020,7 +1039,7 @@ static int atmel_aes_ctr_transfer(struct atmel_aes_dev *dd)
 	struct scatterlist *src, *dst;
 	size_t datalen;
 	u32 ctr;
-	u16 blocks, start, end;
+	u16 start, end;
 	bool use_dma, fragmented = false;
 
 	/* Check for transfer completion. */
@@ -1030,14 +1049,14 @@ static int atmel_aes_ctr_transfer(struct atmel_aes_dev *dd)
 
 	/* Compute data length. */
 	datalen = req->cryptlen - ctx->offset;
-	blocks = DIV_ROUND_UP(datalen, AES_BLOCK_SIZE);
+	ctx->blocks = DIV_ROUND_UP(datalen, AES_BLOCK_SIZE);
 	ctr = be32_to_cpu(ctx->iv[3]);
 
 	/* Check 16bit counter overflow. */
 	start = ctr & 0xffff;
-	end = start + blocks - 1;
+	end = start + ctx->blocks - 1;
 
-	if (blocks >> 16 || end < start) {
+	if (ctx->blocks >> 16 || end < start) {
 		ctr |= 0xffff;
 		datalen = AES_BLOCK_SIZE * (0x10000 - start);
 		fragmented = true;
-- 
2.14.5