Re: [PATCH v2] crypto: inside-secure - Zeroize temporary arrays on stack with sensitive data

[Thomas Huth <thuth@redhat.com>]

On 19/08/2026 13.43, Antoine Tenart wrote:
> On Wed, Aug 19, 2026 at 12:58:36PM +0200, Thomas Huth wrote:
>> 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.
>>
>> Reported-by: Sashiko <sashiko-bot@kernel.org>
>> Link: https://sashiko.dev/#/patchset/20260813134953.979481-1-thuth%40redhat.com
>> Fixes: 38f21b4bab11f ("crypto: inside-secure - Added support for the AES XCBC ahash")
>> Fixes: 7a627db9cafdb ("crypto: inside-secure - Added support for the AES-CMAC ahash")
>> Acked-by: Antoine Tenart <atenart@kernel.org>
>> Signed-off-by: Thomas Huth <thuth@redhat.com>
>> ---
>>   v2: Added "Fixes:" and "Reported-by:" tags
>>   
>>   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;
>>   
>> +
> 
> Sorry, I just noticed there's an extra empty line here.
Oops, that's embarrassing, not sure how I missed that looking at the patch 
multiple times already... Thanks for spotting it, I'll send a v3.

  Thomas