[PATCH 5.5 364/367] crypto: atmel-aes - Fix CTR counter overflow when multiple fragments

Greg Kroah-Hartman
2020-02-10T12:53:01Z

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

[ Upstream commit 3907ccfaec5d9965e306729936fc732c94d2c1e7 ]

The CTR transfer works in fragments of data of maximum 1 MByte because
of the 16 bit CTR counter embedded in the IP. Fix the CTR counter
overflow handling for messages larger than 1 MByte.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: 781a08d9740a ("crypto: atmel-aes - Fix counter overflow in CTR mode")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/crypto/atmel-aes.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/crypto/atmel-aes.c b/drivers/crypto/atmel-aes.c
index ea9dcd7ce799b..b4dee726b2530 100644
--- a/drivers/crypto/atmel-aes.c
+++ b/drivers/crypto/atmel-aes.c
@@ -121,7 +121,7 @@ struct atmel_aes_ctr_ctx {
size_t offset;
struct scatterlist src[2];
struct scatterlist dst[2];
- u16 blocks;
+ u32 blocks;
};

struct atmel_aes_gcm_ctx {
@@ -528,6 +528,12 @@ static void atmel_aes_ctr_update_req_iv(struct atmel_aes_dev *dd)
unsigned int ivsize = crypto_skcipher_ivsize(skcipher);
int i;

+ /*
+ * The CTR transfer works in fragments of data of maximum 1 MByte
+ * because of the 16 bit CTR counter embedded in the IP. When reaching
+ * here, ctx->blocks contains the number of blocks of the last fragment
+ * processed, there is no need to explicit cast it to u16.
+ */
for (i = 0; i < ctx->blocks; i++)
crypto_inc((u8 *)ctx->iv, AES_BLOCK_SIZE);

--
2.20.1