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From:   Tudor Ambarus <tudor.ambarus@microchip.com>
To:     <herbert@gondor.apana.org.au>
CC:     <nicolas.ferre@microchip.com>, <alexandre.belloni@bootlin.com>,
        <ludovic.desroches@microchip.com>, <linux-crypto@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>,
        "Tudor Ambarus" <tudor.ambarus@microchip.com>
Subject: [PATCH 3/9] crypto: atmel-aes: Add blocksize constraint for ECB and CBC modes
Date:   Tue, 20 Jul 2021 11:55:29 +0300
Message-ID: <20210720085535.141486-4-tudor.ambarus@microchip.com>
In-Reply-To: <20210720085535.141486-1-tudor.ambarus@microchip.com>
References: <20210720085535.141486-1-tudor.ambarus@microchip.com>
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NIST 800-38A requires for the ECB and CBC modes that the total number
of bits in the plaintext to be a multiple of the block cipher.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
---
 drivers/crypto/atmel-aes.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/crypto/atmel-aes.c b/drivers/crypto/atmel-aes.c
index b1d286004295..9c6d80d1d7a0 100644
--- a/drivers/crypto/atmel-aes.c
+++ b/drivers/crypto/atmel-aes.c
@@ -1089,6 +1089,11 @@ static int atmel_aes_crypt(struct skcipher_request *req, unsigned long mode)
 	struct atmel_aes_base_ctx *ctx = crypto_skcipher_ctx(skcipher);
 	struct atmel_aes_reqctx *rctx;
 	struct atmel_aes_dev *dd;
+	u32 opmode = mode & AES_FLAGS_OPMODE_MASK;
+
+	if ((opmode == AES_FLAGS_ECB || opmode == AES_FLAGS_CBC) &&
+	    !IS_ALIGNED(req->cryptlen, crypto_skcipher_blocksize(skcipher)))
+		return -EINVAL;
 
 	switch (mode & AES_FLAGS_OPMODE_MASK) {
 	case AES_FLAGS_CFB8:
@@ -1120,7 +1125,7 @@ static int atmel_aes_crypt(struct skcipher_request *req, unsigned long mode)
 	rctx = skcipher_request_ctx(req);
 	rctx->mode = mode;
 
-	if ((mode & AES_FLAGS_OPMODE_MASK) != AES_FLAGS_ECB &&
+	if (opmode != AES_FLAGS_ECB &&
 	    !(mode & AES_FLAGS_ENCRYPT) && req->src == req->dst) {
 		unsigned int ivsize = crypto_skcipher_ivsize(skcipher);
 
-- 
2.25.1