[PATCH] crypto: inside-secure - Zeroize temporary arrays on stack with sensitive data

[PATCH] crypto: inside-secure - Zeroize temporary arrays on stack with sensitive data

[Thomas Huth]

This issue has been found by the Sashiko bot while reviewing another
patch: key_tmp[] in safexcel_xcbcmac_setkey() and consts[] / _const[]
in safexcel_cmac_setkey() contain crypto key material that should not
get exposed to the outside once the function is done. Scrub the arrays
with memzero_explicit() to avoid that the data could leak via the stack.

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 drivers/crypto/inside-secure/safexcel_hash.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/crypto/inside-secure/safexcel_hash.c b/drivers/crypto/inside-secure/safexcel_hash.c
index 3402e570d045c..1ae6fbec31298 100644
--- a/drivers/crypto/inside-secure/safexcel_hash.c
+++ b/drivers/crypto/inside-secure/safexcel_hash.c
@@ -1993,6 +1993,7 @@ static int safexcel_xcbcmac_setkey(struct crypto_ahash *tfm, const u8 *key,
 	ret = aes_prepareenckey(ctx->aes,
 				(u8 *)key_tmp + 2 * AES_BLOCK_SIZE,
 				AES_MIN_KEY_SIZE);
+	memzero_explicit(key_tmp, sizeof(key_tmp));
 	if (ret)
 		return ret;
 
@@ -2104,6 +2105,9 @@ static int safexcel_cmac_setkey(struct crypto_ahash *tfm, const u8 *key,
 	}
 	ctx->cbcmac = false;
 
+
+	memzero_explicit(consts, sizeof(consts));
+	memzero_explicit(_const, sizeof(_const));
 	return 0;
 }
 
-- 
2.55.0

Re: [PATCH] crypto: inside-secure - Zeroize temporary arrays on stack with sensitive data

[Antoine Tenart]

On Fri, Aug 14, 2026 at 10:36:51AM +0200, Thomas Huth wrote:
> This issue has been found by the Sashiko bot while reviewing another
> patch: key_tmp[] in safexcel_xcbcmac_setkey() and consts[] / _const[]
> in safexcel_cmac_setkey() contain crypto key material that should not
> get exposed to the outside once the function is done. Scrub the arrays
> with memzero_explicit() to avoid that the data could leak via the stack.
> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>

This could have both a Reported-by (Sashiko) and a Fixes tag.

With that,

Acked-by: Antoine Tenart <atenart@kernel.org>

Thanks!

> ---
>  drivers/crypto/inside-secure/safexcel_hash.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/crypto/inside-secure/safexcel_hash.c b/drivers/crypto/inside-secure/safexcel_hash.c
> index 3402e570d045c..1ae6fbec31298 100644
> --- a/drivers/crypto/inside-secure/safexcel_hash.c
> +++ b/drivers/crypto/inside-secure/safexcel_hash.c
> @@ -1993,6 +1993,7 @@ static int safexcel_xcbcmac_setkey(struct crypto_ahash *tfm, const u8 *key,
>  	ret = aes_prepareenckey(ctx->aes,
>  				(u8 *)key_tmp + 2 * AES_BLOCK_SIZE,
>  				AES_MIN_KEY_SIZE);
> +	memzero_explicit(key_tmp, sizeof(key_tmp));
>  	if (ret)
>  		return ret;
>  
> @@ -2104,6 +2105,9 @@ static int safexcel_cmac_setkey(struct crypto_ahash *tfm, const u8 *key,
>  	}
>  	ctx->cbcmac = false;
>  
> +
> +	memzero_explicit(consts, sizeof(consts));
> +	memzero_explicit(_const, sizeof(_const));
>  	return 0;
>  }
>  
> -- 
> 2.55.0
>