[PATCH 5.5 184/367] crypto: atmel-aes - Fix counter overflow in CTR mode

Greg Kroah-Hartman
2020-02-10T12:44:44Z

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

commit 781a08d9740afa73357f1a60d45d7c93d7cca2dd upstream.

32 bit counter is not supported by neither of our AES IPs, all implement
a 16 bit block counter. Drop the 32 bit block counter logic.

Fixes: fcac83656a3e ("crypto: atmel-aes - fix the 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/crypto/atmel-aes.c | 37 ++++++++++++-------------------------
1 file changed, 12 insertions(+), 25 deletions(-)

--- a/drivers/crypto/atmel-aes.c
+++ b/drivers/crypto/atmel-aes.c
@@ -89,7 +89,6 @@
struct atmel_aes_caps {
bool has_dualbuff;
bool has_cfb64;
- bool has_ctr32;
bool has_gcm;
bool has_xts;
bool has_authenc;
@@ -1015,8 +1014,9 @@ static int atmel_aes_ctr_transfer(struct
struct atmel_aes_ctr_ctx *ctx = atmel_aes_ctr_ctx_cast(dd->ctx);
struct skcipher_request *req = skcipher_request_cast(dd->areq);
struct scatterlist *src, *dst;
- u32 ctr, blocks;
size_t datalen;
+ u32 ctr;
+ u16 blocks, start, end;
bool use_dma, fragmented = false;

/* Check for transfer completion. */
@@ -1028,27 +1028,17 @@ static int atmel_aes_ctr_transfer(struct
datalen = req->cryptlen - ctx->offset;
blocks = DIV_ROUND_UP(datalen, AES_BLOCK_SIZE);
ctr = be32_to_cpu(ctx->iv[3]);
- if (dd->caps.has_ctr32) {
- /* Check 32bit counter overflow. */
- u32 start = ctr;
- u32 end = start + blocks - 1;
-
- if (end < start) {
- ctr |= 0xffffffff;
- datalen = AES_BLOCK_SIZE * -start;
- fragmented = true;
- }
- } else {
- /* Check 16bit counter overflow. */
- u16 start = ctr & 0xffff;
- u16 end = start + (u16)blocks - 1;
-
- if (blocks >> 16 || end < start) {
- ctr |= 0xffff;
- datalen = AES_BLOCK_SIZE * (0x10000-start);
- fragmented = true;
- }
+
+ /* Check 16bit counter overflow. */
+ start = ctr & 0xffff;
+ end = start + blocks - 1;
+
+ if (blocks >> 16 || end < start) {
+ ctr |= 0xffff;
+ datalen = AES_BLOCK_SIZE * (0x10000 - start);
+ fragmented = true;
}
+
use_dma = (datalen >= ATMEL_AES_DMA_THRESHOLD);

/* Jump to offset. */
@@ -2533,7 +2523,6 @@ static void atmel_aes_get_cap(struct atm
{
dd->caps.has_dualbuff = 0;
dd->caps.has_cfb64 = 0;
- dd->caps.has_ctr32 = 0;
dd->caps.has_gcm = 0;
dd->caps.has_xts = 0;
dd->caps.has_authenc = 0;
@@ -2544,7 +2533,6 @@ static void atmel_aes_get_cap(struct atm
case 0x500:
dd->caps.has_dualbuff = 1;
dd->caps.has_cfb64 = 1;
- dd->caps.has_ctr32 = 1;
dd->caps.has_gcm = 1;
dd->caps.has_xts = 1;
dd->caps.has_authenc = 1;
@@ -2553,7 +2541,6 @@ static void atmel_aes_get_cap(struct atm
case 0x200:
dd->caps.has_dualbuff = 1;
dd->caps.has_cfb64 = 1;
- dd->caps.has_ctr32 = 1;
dd->caps.has_gcm = 1;
dd->caps.max_burst_size = 4;
break;