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Subject[PATCH 3/4] crypto: atmel-aes - Detecting in-place operations two sg lists
Date
From: Ryan Wanner <Ryan.Wanner@microchip.com>

Avoiding detecting finely in-place operations with different
scatter lists. Copying the source data for decryption into rctx->lastc
regardless if the operation is in-place or not. This allows in-place
operations with different scatter lists.

This approach takes less resources than parsing both scatter lists to
check if they are equal.

Signed-off-by: Ryan Wanner <Ryan.Wanner@microchip.com>
---
drivers/crypto/atmel-aes.c | 14 ++++----------
1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/drivers/crypto/atmel-aes.c b/drivers/crypto/atmel-aes.c
index 063394cfa874..08a923c2a0eb 100644
--- a/drivers/crypto/atmel-aes.c
+++ b/drivers/crypto/atmel-aes.c
@@ -493,17 +493,11 @@ static void atmel_aes_set_iv_as_last_ciphertext_block(struct atmel_aes_dev *dd)
if (req->cryptlen < ivsize)
return;

- if (rctx->mode & AES_FLAGS_ENCRYPT) {
+ if (rctx->mode & AES_FLAGS_ENCRYPT)
scatterwalk_map_and_copy(req->iv, req->dst,
req->cryptlen - ivsize, ivsize, 0);
- } else {
- if (req->src == req->dst)
- memcpy(req->iv, rctx->lastc, ivsize);
- else
- scatterwalk_map_and_copy(req->iv, req->src,
- req->cryptlen - ivsize,
- ivsize, 0);
- }
+ else
+ memcpy(req->iv, rctx->lastc, ivsize);
}

static inline struct atmel_aes_ctr_ctx *
@@ -1146,7 +1140,7 @@ static int atmel_aes_crypt(struct skcipher_request *req, unsigned long mode)
rctx->mode = mode;

if (opmode != AES_FLAGS_ECB &&
- !(mode & AES_FLAGS_ENCRYPT) && req->src == req->dst) {
+ !(mode & AES_FLAGS_ENCRYPT)) {
unsigned int ivsize = crypto_skcipher_ivsize(skcipher);

if (req->cryptlen >= ivsize)
--
2.37.2
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