[PATCH v1 2/3] s390/crypto: Fix missing scrub of temp buffers with PAES algorithm

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

In function ctr_paes_do_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.

In function __xts_2keys_prep_param() change the existing scrub to
clean the whole param block instead of just the key field.

Fixes: 6cd87cb5ef6c ("s390/crypto: Rework protected key AES for true asynch support")
Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Cc: stable@vger.kernel.org # 6.16+
---
 arch/s390/crypto/paes_s390.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/s390/crypto/paes_s390.c b/arch/s390/crypto/paes_s390.c
index ccc7da106c3a..5a7dc4651885 100644
--- a/arch/s390/crypto/paes_s390.c
+++ b/arch/s390/crypto/paes_s390.c
@@ -1041,6 +1041,7 @@ static int ctr_paes_do_crypt(struct s390_paes_ctx *ctx,
 		memcpy(walk->dst.virt.addr, buf, nbytes);
 		crypto_inc(walk->iv, AES_BLOCK_SIZE);
 		rc = skcipher_walk_done(walk, 0);
+		memzero_explicit(buf, sizeof(buf));
 	}
 
 out:
@@ -1377,7 +1378,7 @@ static inline int __xts_2keys_prep_param(struct s390_pxts_ctx *ctx,
 		memcpy(param->init, pcc_param.xts, 16);
 	}
 
-	memzero_explicit(pcc_param.key, sizeof(pcc_param.key));
+	memzero_explicit(&pcc_param, sizeof(pcc_param));
 	return rc;
 }
 
-- 
2.43.0