[PATCH v2 2/2] s390/crypto: Explicit scrub temp buffer in AES ctr mode algorithm

[Harald Freudenberger <freude@linux.ibm.com>]

In function ctr_aes_crypt() there is a buffer used to process
remaining bytes < AES_BLOCK_SIZE. This buffer was not scrubbed and
thus could lead to expose of unwanted data.

When the buffer is used explicitly scrub it at the end of the code
block to avoid exposure of maybe sensitive data.

Fixes: d07f951903fa ("crypto: s390/aes - Fix buffer overread in CTR mode")
Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Cc: stable@vger.kernel.org # 6.8+
---
 arch/s390/crypto/aes_s390.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/s390/crypto/aes_s390.c b/arch/s390/crypto/aes_s390.c
index 366ce22d3623..f52c612ae9cb 100644
--- a/arch/s390/crypto/aes_s390.c
+++ b/arch/s390/crypto/aes_s390.c
@@ -604,6 +604,7 @@ static int ctr_aes_crypt(struct skcipher_request *req)
 		memcpy(walk.dst.virt.addr, buf, nbytes);
 		crypto_inc(walk.iv, AES_BLOCK_SIZE);
 		ret = skcipher_walk_done(&walk, 0);
+		memzero_explicit(buf, sizeof(buf));
 	}
 
 	return ret;
-- 
2.43.0