netdev - Re: [PATCH net 4/4] tls: Fix tls

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Message-ID: <1ee3aef8-7074-79d3-06d6-293d258139a1@mellanox.com>
Date:   Wed, 27 Feb 2019 15:26:40 +0000
From:   Boris Pismenny <borisp@...lanox.com>
To:     Dave Watson <davejwatson@...com>
CC:     Aviad Yehezkel <aviadye@...lanox.com>,
        "john.fastabend@...il.com" <john.fastabend@...il.com>,
        "daniel@...earbox.net" <daniel@...earbox.net>,
        "vakul.garg@....com" <vakul.garg@....com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        Eran Ben Elisha <eranbe@...lanox.com>
Subject: Re: [PATCH net 4/4] tls: Fix tls_device receive



On 2/26/2019 10:34 PM, Dave Watson wrote:
> On 02/26/19 02:12 PM, Boris Pismenny wrote:
>> Currently, the receive function fails to handle records already
>> decrypted by the device due to the commit mentioned below.
>>
>> This commit advances the TLS record sequence number and prepares the context
>> to handle the next record.
>>
>> Fixes: fedf201e1296 ("net: tls: Refactor control message handling on recv")
>> Signed-off-by: Boris Pismenny <borisp@...lanox.com>
>> Reviewed-by: Eran Ben Elisha <eranbe@...lanox.com>
>> ---
>>   net/tls/tls_sw.c | 15 +++++++--------
>>   1 file changed, 7 insertions(+), 8 deletions(-)
>>
>> diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
>> index f515cd7e984e..85da10182d8d 100644
>> --- a/net/tls/tls_sw.c
>> +++ b/net/tls/tls_sw.c
>> @@ -1481,18 +1481,17 @@ static int decrypt_skb_update(struct sock *sk, struct sk_buff *skb,
>>   
>>   			return err;
>>   		}
>> -
>> -		rxm->full_len -= padding_length(ctx, tls_ctx, skb);
>> -
>> -		rxm->offset += prot->prepend_size;
>> -		rxm->full_len -= prot->overhead_size;
>> -		tls_advance_record_sn(sk, &tls_ctx->rx, version);
>> -		ctx->decrypted = true;
>> -		ctx->saved_data_ready(sk);
>>   	} else {
>>   		*zc = false;
>>   	}
>>   
>> +	rxm->full_len -= padding_length(ctx, tls_ctx, skb);
>> +	rxm->offset += prot->prepend_size;
>> +	rxm->full_len -= prot->overhead_size;
>> +	tls_advance_record_sn(sk, &tls_ctx->rx, version);
>> +	ctx->decrypted = true;
>> +	ctx->saved_data_ready(sk);
>> +
>>   	return err;
>>   }
> 
> This breaks the tls.control_msg test:
> 
>    [ RUN      ] tls.control_msg
>    tls.c:764:tls.control_msg:Expected memcmp(buf, test_str, send_len) (18446744073709551614) == 0 (0)
>    tls.c:777:tls.control_msg:Expected memcmp(buf, test_str, send_len) (18446744073709551614) == 0 (0)
>    tls.control_msg: Test failed at step #8
> 
> So either control message handling needs to only call
> decrypt_skb_update once, or we need a new flag or something to handle
> the device case
> 

Thanks for raising this, I'm not used to the kselftests yet.
I've refactored the code here to get this working.
Will send V2 soon.