[PATCH] crypto: atmel-aes - properly set IV after {en,de}crypt
From: Romain Izard <hidden>
Date: 2017-10-06 15:51:22
Also in:
linux-arm-kernel, lkml
Subsystem:
crypto api, the rest · Maintainers:
Herbert Xu, "David S. Miller", Linus Torvalds
Certain cipher modes like CTS expect the IV (req->info) of
ablkcipher_request (or equivalently req->iv of skcipher_request) to
contain the last ciphertext block when the {en,de}crypt operation is done.
Fix this issue for the Atmel AES hardware engine. The tcrypt test
case for cts(cbc(aes)) is now correctly passed.
To handle the case of in-place decryption, copy the ciphertext in an
intermediate buffer before decryption.
Signed-off-by: Romain Izard <redacted>
---
drivers/crypto/atmel-aes.c | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)
diff --git a/drivers/crypto/atmel-aes.c b/drivers/crypto/atmel-aes.c
index 29e20c37f3a6..f22300babb45 100644
--- a/drivers/crypto/atmel-aes.c
+++ b/drivers/crypto/atmel-aes.c@@ -156,6 +156,7 @@ struct atmel_aes_authenc_ctx { struct atmel_aes_reqctx { unsigned long mode; + u8 *backup_info; }; #ifdef CONFIG_CRYPTO_DEV_ATMEL_AUTHENC
@@ -496,6 +497,12 @@ static void atmel_aes_authenc_complete(struct atmel_aes_dev *dd, int err); static inline int atmel_aes_complete(struct atmel_aes_dev *dd, int err) { + struct ablkcipher_request *req = ablkcipher_request_cast(dd->areq); + struct crypto_ablkcipher *ablkcipher = crypto_ablkcipher_reqtfm(req); + struct atmel_aes_reqctx *rctx = ablkcipher_request_ctx(req); + int ivsize = crypto_ablkcipher_ivsize(ablkcipher); + bool enc = atmel_aes_is_encrypt(dd); + #ifdef CONFIG_CRYPTO_DEV_ATMEL_AUTHENC atmel_aes_authenc_complete(dd, err); #endif
@@ -503,6 +510,15 @@ static inline int atmel_aes_complete(struct atmel_aes_dev *dd, int err) clk_disable(dd->iclk); dd->flags &= ~AES_FLAGS_BUSY; + if (enc) { + scatterwalk_map_and_copy(req->info, req->dst, + req->nbytes - ivsize, ivsize, 0); + } else if (rctx->backup_info) { + memcpy(req->info, rctx->backup_info, ivsize); + kfree(rctx->backup_info); + rctx->backup_info = NULL; + } + if (dd->is_async) dd->areq->complete(dd->areq, err);
@@ -959,13 +975,25 @@ static int atmel_aes_transfer_complete(struct atmel_aes_dev *dd) static int atmel_aes_start(struct atmel_aes_dev *dd) { struct ablkcipher_request *req = ablkcipher_request_cast(dd->areq); + struct crypto_ablkcipher *ablkcipher = crypto_ablkcipher_reqtfm(req); struct atmel_aes_reqctx *rctx = ablkcipher_request_ctx(req); + int ivsize = crypto_ablkcipher_ivsize(ablkcipher); + bool enc = atmel_aes_is_encrypt(dd); bool use_dma = (req->nbytes >= ATMEL_AES_DMA_THRESHOLD || dd->ctx->block_size != AES_BLOCK_SIZE); int err; atmel_aes_set_mode(dd, rctx); + if (!enc) { + rctx->backup_info = kzalloc(ivsize, GFP_KERNEL); + if (rctx->backup_info == NULL) + return atmel_aes_complete(dd, -ENOMEM); + + scatterwalk_map_and_copy(rctx->backup_info, req->src, + (req->nbytes - ivsize), ivsize, 0); + } + err = atmel_aes_hw_init(dd); if (err) return atmel_aes_complete(dd, err);
--
2.11.0