linux-kernel - Re: [PATCH 1/7] crypto: qce: common: Add MAC failed error checking

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Date:   Tue, 13 Apr 2021 15:28:22 -0400
From:   Thara Gopinath <thara.gopinath@...aro.org>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     herbert@...dor.apana.org.au, davem@...emloft.net,
        ebiggers@...gle.com, ardb@...nel.org, sivaprak@...eaurora.org,
        linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/7] crypto: qce: common: Add MAC failed error checking

Hi Bjorn,

Thanks for the reviews.
I realized that I had these replies in my draft for a while and forgot 
to send them!

On 4/5/21 1:36 PM, Bjorn Andersson wrote:
> On Thu 25 Feb 12:27 CST 2021, Thara Gopinath wrote:
> 
>> MAC_FAILED gets set in the status register if authenthication fails
>> for ccm algorithms(during decryption). Add support to catch and flag
>> this error.
>>
>> Signed-off-by: Thara Gopinath <thara.gopinath@...aro.org>
>> ---
>>   drivers/crypto/qce/common.c | 11 ++++++++---
>>   1 file changed, 8 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/crypto/qce/common.c b/drivers/crypto/qce/common.c
>> index dceb9579d87a..7c3cb483749e 100644
>> --- a/drivers/crypto/qce/common.c
>> +++ b/drivers/crypto/qce/common.c
>> @@ -403,7 +403,8 @@ int qce_start(struct crypto_async_request *async_req, u32 type)
>>   }
>>   
>>   #define STATUS_ERRORS	\
>> -		(BIT(SW_ERR_SHIFT) | BIT(AXI_ERR_SHIFT) | BIT(HSD_ERR_SHIFT))
>> +		(BIT(SW_ERR_SHIFT) | BIT(AXI_ERR_SHIFT) |	\
>> +		 BIT(HSD_ERR_SHIFT) | BIT(MAC_FAILED_SHIFT))
>>   
>>   int qce_check_status(struct qce_device *qce, u32 *status)
>>   {
>> @@ -417,8 +418,12 @@ int qce_check_status(struct qce_device *qce, u32 *status)
>>   	 * use result_status from result dump the result_status needs to be byte
>>   	 * swapped, since we set the device to little endian.
>>   	 */
>> -	if (*status & STATUS_ERRORS || !(*status & BIT(OPERATION_DONE_SHIFT)))
>> -		ret = -ENXIO;
>> +	if (*status & STATUS_ERRORS || !(*status & BIT(OPERATION_DONE_SHIFT))) {
>> +		if (*status & BIT(MAC_FAILED_SHIFT))
> 
> Afaict MAC_FAILED indicates a different category of errors from the
> others. So I would prefer that the conditionals are flattened.
> 
> Is OPERATION_DONE set when MAC_FAILED?
Yes it is. I will change the check to the pattern you have suggested. It 
is less confusing..

> 
> If so:
> 
> if (errors || !done)
> 	return -ENXIO;
> else if (*status & BIT(MAC_FAILED))
> 	return -EBADMSG;
> 
> Would be cleaner in my opinion.
> 
> Regards,
> Bjorn
> 
>> +			ret = -EBADMSG;
>> +		else
>> +			ret = -ENXIO;
>> +	}
>>   
>>   	return ret;
>>   }
>> -- 
>> 2.25.1
>>

-- 
Warm Regards
Thara